1. I'd be fine with posting it out in the open. That way it's easier to have someone post "Byntrou catches everyone up on the day's events" or something similarly short, since the other players can read or not as they choose. If someone wants to leave info out, I figure it's easy to say "I tell them everything except about that visit from the man in the hood" or whatever. And in that case, it's probably easier to detail what you're leaving out than to try to detail everything you're keeping in your account, as well.
2. I'm actually new to the PbP games. I'm in several, but none of them have reached a point where the DM has doled out XP. I'd be fine with XP listed in the OOC thread, myself.
3. I think this would depend on how you'd like to handle leveling. I'd say, whether or not it's enough to level, it makes sense to hand out XP whenever the characters are in a situation where you as a DM would consider them capable of leveling given enough XP. If that means they need to have several free weeks, then that's when the XP is handed out. If they only need a free day or two, or they can do it on the road provided there are no encounters, or whatever, do it then.
jason