Let everyone go at least twice and invite them back next week. Be flexible with your practice schedules. I know of one team which used to practice on Sunday mornings over breakfast. Knowledge Bowel Team practice is a lot easier than Hot Food because you do not need a kitchen. Time your answers.
Timing is as important as the answers.
Once you have your team, let them divide up the books and each one starts to learn. That goes for more than one alternate as well. Unless you have a clear cut choice, hold up on choosing a captain. Your captain will usually evolve and the team will make the choice, saving you from having to hurt someone's feelings. Of course if it does not happen, then you must make the decision.