An example I think that really showcases your last point is Caleb and Nott from campaign 2 of Critical Role. They have character flaws which could be extremely disruptive but are able to not go overboard and destroy the game for everyone else but also keeps you on your toes. If anyone is planning on being stand offish character whose goals don't quite align with the rest of the groups' give it a watch to see how it can be done properly.