My team ALWAYS has to be the same level. I get rather obsessive about this, and even try getting them at the same EXP level.
I NEVER really use my starters. I feel it is very overused and I want the feeling that my team is different to others. I sometimes only play with Pokemon which I never used or seen anyone used before. I also don't use any legendaries in-game.
Also, weird enough I haven't yet to train properly a Flying Pokemon. The only Flying Pokemon I have in my party is my Lvl.5 Pidove, who is only responsible for flying.