Yeah, probably shouldn't form character connections until you're one of the approved people
Otherwise someone could get chosen and you don't and then it would all be for nothing
That's partially true, bro.
As I've submitted my character sheet for Brad, I've mentioned three character spots that I'm looking to be filled- the head cheerleader, the nerd victim and Brad's best friend. Anyone is more than welcome to apply to any of those spots. If we happen to decide to accept someone else into that spot, but we still want your character in the game, there is no reason the character can't be altered to cut that connection out.
What I would like to discourage you from is any form of bickering about game spots. Remember, one of the most important things for us, as the GMs of this game, is to have a team of players that can get along, have fun together and create interesting group dynamics.