Hello and welcome to Just Answers. This is Dr. O.
I am so sorry to hear about the problems you are having with Miko. I think I can help. I am going to attach a lot of information after making two suggestions. Please read it and let me know if you have any questions.
Suggestions:
Purchase a product called Feliway. Use as directed on the label. Important to read the entire label.
Make sure there is at least 1 litter pan per cat per household. Since you are having urinary problems increase that to 2-3 litter pans for Miko.
If that does not work, read the following...
-Dr. O. 
The following information is adapted from presentations originally composed by Lore I. Haug, DVM in the Department of Small Animal Behavior at Texas A&M University.
Feline inappropriate urination is a not too uncommon problem seen among cats especially in multi cat households. This usually becomes an issue as a result of some sort of stressor, such as moving to a new home, introducing new animals into the house, pregnancy of the owner, the new baby in the house, or some other change in routine or habit.
NORMAL BEHAVIOR
But before we go too much further I want to explain some normal anomalies in kitten and cat behavior. In a young, growing, developing kittens it normally takes at least 40 days of life before they begin to develop a reflex in the ranging as which sends a signal to the brain indicating that they need to go to the bathroom. You can think of this much as the same way that young humans have problems potty training. There is any anatomical development of that has to occur on the nerves of the body before urinary and fecal continence is able to happen. It is around this time frame that we see kittens beginning to play and eat litter. The covering behavior is a learned behavior.
Normal adult cat behavior happens sequentially where my the animal enters a preferential area, digs a hole in a soft substrate (litter), eliminates, smells of the excreta, and covers the excreta if in their home area.
Urine spraying is also a normal cat behavior used to mark territory to ward off other cats from entering an area and to communicate to the homesteaded cat that an aggressor has entered their territory. This behavior is also seen in times of stress, which is abnormal. Urine spraying is normal even in altered house cats. It happens in about 10% of male cat and about 5% of female cats.
HOUSETRAINING
House training is a management issue which involves the prevention of animal expression of inappropriate behavior, confinement and supervision, allowing frequent opportunity's to eliminate an appropriate areas, and a good litter box management. House training modification involves positive reinforcement of desired behaviors, neutrally interrupting inappropriate behaviors, restricting the animal to appropriate surfaces, and maintaining consistent schedules, routines and expectations.
LITTERBOX MANAGEMENT
Although it may seem like common sense I feel is necessary to cover the basics regarding litter box management because oftentimes behavioral issues are often brought about by mistakes made by owners. The litter box must be in an appropriate location. What I mean by this is that it must be accessible, it should be located in a private area and away from disturbing environmental stimuli. Additionally, good litterbox management requires appropriate hygiene. At minimum, the litter should be scooped 1-2 times every day (7 days a week), the litter changed every 7-30 days, and the litter pan cleaned with a mild, inoffensive cleaner (soap and water).
In addition to all of the above, one must choose an appropriate litter. When choosing a product it is best to choose one that is soft and absorbent, avoiding any deodorants, and avoid any abrupt changes. There should be at least one litter pan per cat per household. The size of the box should be proportional to the animal. That is, if you have a larger breed cat make sure that there is adequate room for him\her to easily enter and exit and have enough room while they are inside.
INAPPROPRIATE URINATION
Problem solving inappropriate urination is never an easy process. Rarely does the first treatment solve the problem, or if it does it may not be a permanent solution. There are certain breeds that are predisposed to inappropriate urination such as Himalayan and Persians. A medical evaluation is essential in every housesoiling case, no exceptions. Many cases of housesoiling arise from, or are complicated by medical issues. Failure to address a physical medical issue before a behavioral medical issue has be potential to result in devastating consequences. At minimum, a medical work-up should involve a urinalysis and/or fecal float +/- fecal smear. The first part of formulating a solution is gathering all of the information that has led up to the problem, usually looking back at least 90 days. Be prepared to answer the following:
What is the nature of the problem?
Be prepared to list litter pan hygiene and location.
Give details about the environment?
List any social issues such as inter-cat and/or interspecies rivalry.
What type of inappropriate behavior is occurring, urine, feces, or both?
Which animal is it, or are there multiple animals involved?
When does it occur?
Where does it occur?
When did the problem first start and how long has it been going on?
How often does the problem(s) occur?
Is it consistently occurring?
It the behavior an isolated episode?
Has there been any previous treatments and what was the outcome?
When dealing with an inappropriate elimination issue ask yourself if you are following the basic tenants of feline husbandry listed above.
-Do I have the right type, depth, frequency of cleaning, and method of cleaning the litter?
-Have I offered enough litter pans and of the right characteristics (covered, pan height, etc.)?
-Are the locations of the litter pans inviting?
To elaborate on the last question one must ask, what is near the litter box? Where does the animal have to go to get to, or what obstacles does the animal have to navigate to reach the elimination area? Are there pet doors in the way? Is the pan location in an open or secluded area?
Some social issues that may lead to inappropriate elimination in multi-animal households include frank aggression, chasing, starring, or allogrooming. Internal strife is a common cause for feline housesoiling.
THE PROBLEM
If a cat is experiencing inappropriate defecation, urination or urine spraying one must identify if it is a housesoiling issue or a marking issue. Some things to consider are inadequate housetraining and inadequate access to appropriate elimination areas. If an animal is restricted to the preferential elimination area by temporal, physical, environmental, and behavioral constraints. In order to differentiate between housesoiling or marking one must determine if there is a surface preference or aversion, and a location preference or aversion. Cats prefer a surface that is soft, and absorbent such as carpet, or fabric (bathmats, bedspreads, clothes). Substrate preference may be a a primary or secondary problem to other issues. Substrate aversion is usually a primary issue, but can develop secondary to medical issues and usually an aversion to the litter being used however, they can also develop aversions to the characteristics of the litter box. The signs of litter box aversion may include housesoiling directly outside the box, resistant or hesitant to enter the box, the cat does not spend much time in the box, or he\she may try to stand on the edge of the box. In general, cats select one or two areas in the house or yard as a location preference. Location aversion is usually displayed as an animal eliminating indiscriminately in several other areas in their environment. Look for adjacent environmental problems such as appliances, other animals, and doorways.
TREATMENT OF HOUSESOILING
In order to properly treat an animal for housesoiling all of the problems must first be identified. Once those problems have been identified a concerted effort can be made to choose the most efficient treatments for resolving the issues. Prevent the animal from eliminating in the undesirable area. This can be accomplished by one or a combination of the following: confinement, local aversion therapy, altering the function of the location. Additionally, one must clean the soiled areas very well with an odor neutralizer. There are a variety of over the counter products suitable for this purpose. One must also implement adequate litter box management. Be sure the cat has adequate access to the box, this is especially important in multi cat households or a large household. Begin a litter box preference test. This can be done by offering 2-3 boxes simultaneously and adjacent to each other using varying characteristics such as litterpan height, size of the litter pan, covered or uncovered, litter texture, amount of litter in the pan, or any other litter or litterpan characteristics. Alter one aspect every 3 to 7 days and keep a journal of the box and its usage. One other treatment is to trim long haired cats.
TREATMENT OF URINE MARKING
Treatment of urine marking involves successfully identifying and altering environmental triggers such as olfactory, visual, and any new items such as furniture or plants. Some animals are very reactive two olfactory stimuli such as dirty laundry, gym bags, pet bedding, dead animals, and feces. Some animals urine mark due to social triggers which can be anxiety, stress, up or status related. Certain social triggers include animals coming in or outside of their territory, humans coming in or out of the territory, and separation from other animals. In order to treat this one must prevent access to stimuli to trigger the behavior. This can be done by separating cats if they have social issues, blocking access to outside cats and practicing good hygiene by putting away dirty laundry. Prevent an animal's access to previously so well the areas, if possible. Clean previously soiled areas very well with an odor neutralizer. Management of social stimuli can be overcome by encouraging behavioral separation and providing multiple resource locations. A reduction in environmental stimuli can be overcome by reducing environmental changes and the introduction of new odors or items gradually and in a very controlled fashion thereby minimizing stress. One must also address social issues by desensitization or counterconditioning outdoor cats, indoor cats, or specific humans.
PHARMACEUTICAL INTERVENTION
Occasionally the use of medications are necessary either short term, long-term, or intermittently to assist in behavioral modification. Some commonly used medications are fluoxetine which is most efficacious for spraying as well as clomipramine. The specific choice of medication is best determined by your veterinarian. Many cats receive additional benefits from using pheromone therapy that can be found in such products as Feliway.
Disobedience does not exist, it is a reflection of insufficient training.