I was apparently lost in the shuffle, so when I contacted them a week before my start date to ask what was going on, they came back three days later with a single team.

I met with the team, and told my recruiter that I didn't mind working with them (though it's not clear what would have happened if I had). I was then given a form with room for a dozen teams, and asked to rank my only choice on a scale from 1-10.