Boris, you should probally avoid beer for now, but I can drink beer without any problems. In fact any carbonated drinks are fine (cola/lemonade etc). Last weekend I had 5 or 6 beers and 4 alcopops with a few shots of spirit too and was ok. It is VERY rare I do this though. In fact only once since my operation 6 months ago.
Drinking water is important and hard. When I drink lots of water my consistency is worse and I have to visit the bathroom more. Drink slowly and regularly, prefereably AFTER food. 2 litres of water is the recommended amount for EVERYONE, not just people with J-Pouch.
Peanut butter shouldn't cause you any issues. Its considered safe for all J-Pouchs.