I thought it was standard to have a leak proof test before takedown. If you had a successful barium enema before final takedown to test the pouch for leaks then you have no worries, it is leakproof. That stuff will find a way out if there is one.
I took it slow with foods but gradually got back to my normal diet. I actually put on too much weight. You will know if some food plays up, so best to avoid it. Onions do it for me, love them but they do not love me. I am also now just over the borderline on lactose intolerance, so I have lactose free dairy.
Night time is the worst, but you can do some things to minimise this. Depending on your metabolism, you will know how long things take to go through you. Avoid big heavy meals later in the day, and try to purge some time in the evening. Also, sometimes it is just gas, so try laying on your stomach to pass this. That will definitely cut down on bathroom time.
You will never be free of some drugs, and Imodium or lomotil or a combination will help control output, but again you need to experiment timing and doses that work for you.
Finally, don't always get up at the first sign of pressure. Sometimes if you wait, you go back to sleep and sneak in an extra hour or two. This is definitely one that you need to work out for yourself and is the riskiest. Be prepared for a few errors in judgement, it is not life threatening
Good luck and hang in there, if you can get your pouch behaving then it is a good start and you can live, almost, normally.