Your best bet is to find a renal dietitian and follow that diet. If you don't follow the renal plan, you can get into serious trouble with your kidney and your heart. And it can happen fast with things like potassium. Try to compensate with the diabetes as best you can. Is your husband on insulin? That will make things a bit easier. You can find good renal cookbooks on most online book stores.
You will need to speak to your nephrologist to find out what he/she has to say about what is in the various brands. Sorry, but it's been a long time for me and I don't remember what was ok. Also ask the pharmacist to see which ones are contraindicated on the labels.
Because of imbalances in calcium and phosphorus, you can get boneloss due to kidney issues. I didn't have any pain, but I know that I lost bone mass during this time and while I was on dialysis. Things improved after my transplant. I would talk to your doc and try to determine the source of the pain. It could be something unrelated like arthritis.
Often the itching is due to high phosphorus levels. Do you know what hers is? Has she been checked recently? Try cutting back on dairy, legumes, and nuts as these are high phosphorus foods.
I had this problem while on dialysis (due to phosphorus) and found that the occasional oatmeal bath messy but helpful. I rinsed off afterwards and it was a pain to clean the tub though. She will need help.
As far as I know (I'm a biologist, not a doc) there is no connection between a double ureter (a physical plumbing issue) with incontinence (neuro-muscular issue). My cousin gave me a kidney with a double ureter and neither one of us have had problems.
I'm glad you've gotten a diagnosis. I know that some supplements are helpful for peripheral neuropathy, but don't know if they help with the autonomic stuff. These are ALA (alpha lipoic acid), GLA (gamma linolenic acid) and vitamin C taken in combination. You might want to try this. Check with your docs first though.
I've had many of the issues that you do (I'm now 10 years almost post transplant) and while I have never had this issue, it sounds like some sort of neuropathy to me. Since it is worse when potassium is high, this makes a bit of sense too as potassium can affect nerve function. Do you have autonomic neuropathy? Sorry I can't be more help but that is my best guess.
You really need to see a doc and get regular kidney lab work done. It tends to progress silently until you suddenly get symptoms. You could be anemic due to the kidneys. In some cases iron supplements help, but in many cases of kidney issues, the iron isn't absorbed that well and needs to be administered intravenously. Many kidney patients have this done. The cramping could be due to an electrolyte imbalance as well. What you are allowed to eat is often dictated by what your labwork says.
In the meantime work on cutting back on sodium (especially from processed food - it has a lot). If you have no swelling, I would also try to hydrate well as this helps take some of the pressure off the kidneys.
My transplant center did a study on kidney donors and some of the things they found were that women who wanted to get pregnant had no harder time doing so and had no higher incidence of miscarriage or birth defects. You will still need to be monitored, but kidney donors who have only one remaining kidney do get pregnant and have successful families.