I was hoping to get more information on how many dogs and what the problems were since it wasn't entirely clear in the original question but let me try to help you.
The dog sho is rushing outside to drink and drinking from the toilet likely needs to see your vet. It is possibly he has a urinary tract infection. Common symptoms of a urinary tract infection are frequent urination, dribbling urine, blood in the urine, squatting frequently to urinate, strong odor to the urine, inappropriate urination and straining to urinate as well as an increase in fluid intake. A dog with a UTI does not always show all the symptoms and typically displays 2 or 3. I believe you need to have your Vet check your dog out so it can get medication for the problem if your dog is displaying 2 or more of the above symptoms.. Cushings can cause panting as well and excessive thirst.
Other causes for increased thirst and frequent urination include kidney failure, diabetes mellitus, cushing, a uterine infection (called pyometra), and liver disease to name a few. You can read about this here:
So that dog needs to be seen and have testing done to determine that his organs are functioning properly and there is no infection present.
For the other dog, you need to start him on obedience training in order to control him. The following site is helpful in helping owners train their dog. Be sure and click on the link to the page on obedience at the bottom. and links on subsequent pages leading to detailed instructions.
Training works best if you train at least 30 minutes a day (two 15 minute sessions). I would start making your dog work via the Nothing in life is free program (NILF). It is outlined below.
I know this is a lot of time to devote toward training, but when someone knocks on the door and you can tell your dog to sit and stay when visitors come in the door, you will be so proud that you won't regret one minute of the time you devoted to training.
You will also want to keep a leash on your dog at all times initially to grab if there is any disobedience. I think you will be pleasantly surprised at how well your dog does with additional training and practice. Dogs like knowing what is expected of them and they love the little paper thin slices of hotdogs that I use for treats while training. They also prefer the owner be the alpha as it takes the stress off them. Give this a try and see how it works for you.
There are some things you can do before your dog is obedience trained to aid in stopping the behavior. For barking, as crazy as it seems, you may want to teach the speak command and then the quiet command. It seems easier to teach the quiet command after your dog has learned the speak command. The following site explains teaching speak and quiet commands.
If this doesn't work, you may have to try a citronella bark collar. If you have someone they try to do this to on a regular, this person could be elected to help with training allowing you to work with her several times a day when you know they would normally do it. Once they stop barking or rushing the door, reward them with tasty treats and praise. For each person he doesn't do this to, reward them. She will learn that strangers mean treats and are a good thing and that should help stop the rushing.
In addition, if you are present when this is occurring, you can give a correction using the attached leash(good reason to keep it attached) when he looks like she wants to rush the door. A quick short tug and firm NO will help teach him that you find it unacceptable.
When first teaching him to sit at the door when visitors come, you can slip the leash under your foot, have him sit and use the leash to keep him in that spot in a sit or down position as you open the door. Initially he will fight it, but soon will realize it doesn't do any good to try and move away and will stay. When he does that reward him. Have visitors reward him as well. Let visitors be seated before releasing him that way everything is calmer. You can even keep him with you and command him to sit or lay down in the room your visitors and you are in.
In addition, if the situation is not improving using the techniques I describe, you may have to consult a professional behaviorist. You can usually find a behaviorist by asking your Vet for a recommendation or you may be able to find one using the following site.
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Since there have been recalls on certain foods, please check the following site to be sure the food your animals eat is not affected. If it is affected, contact your vet as soon as possible. Have your dog seen if they have any symptoms.