Probably this is the kind of thing that is good to PM a mod about as opposed to creating a thread. You should check out the Rules thread in this forum. =]
To answer the question, that depends. Check out the existing threads promoting the various games people are working on, and learn from that. Act like a part of the community talking about your game to your community and I can’t imagine that there would be any problem. net net: shouldn’t be any problem.
no.
no you wont get banned.
as a matter of fact…skullgirls creators posted up their ideas here for feedback while they were just beginning to character design and create the game. I think even before drawing any sprites or anything.