I am sorry to hear you are worried about Boo. My name is Rebecca. I am a veterinarian and will do my best to help.
Gripe water may help with dehydration if she is dehydrated, and many constipated cats do become dehydrated. However, if she is vomiting, she may not be able to keep it down. Gripe water will probably not help relieve constipation, or incontinence, or with the vomiting. Be careful not to use gripe water that is sweetened at all.
For constipation, I usually treat with fluids, stool softeners like Mira Lax, and enemas if necessary (not any over the counter enemas; they are not safe in cats not even ones for infants. They contain phosphates which can be dangerous. You need to get something like Pet Enema, with only DSS as the active ingredient).
For incontinence, you need to find the underlying cause: excessive drinking (kidney disease, diabetes, hyperthyroidism, neurologic disease) and treat for it.
Vomiting can be from dozens of conditions. You can try famotidine (Pepcid AC) at 1/4th of a 10 mg tablet twice daily, but it is best to find and treat the underlying problem.
Have any blood tests been done recently?
Let me know what other questions I can answer. Rebecca