Like I said, a lot of these symptoms seem to be characteristic of both the condition (inflammation in the pouch and consequent dehydration) and the treatment. No, I've never taken them separately. My dad has a pouch too, and he takes flagyl alone, I believe, when things flare up (rarely, for him).
I was initially reluctant to go on cipro/flagyl for this increasingly chronic issue. I know the dangers of antibiotics generally, and cipro/flagyl specifically. But they work(ed), so I was willing to take the risk.
Ringing in the ears is noted in the side effects list for cipro in drugs.com. Also if you do a google search for cipro and ears ringing, there is some anecdotal evidence. No, I don't believe I experienced that before the long periods of cipro this year.
With every medical intervention I've tried since I got my UC diagnosis, if there was a nasty side effect to be had, I had it. I guess I'm just lucky that way 
My insurance company was on strike until just a few weeks ago, so getting information from them was very difficult. I'll make the inquiry about Xifaxan.