I think they'd judge the team as a whole, rather than individuals. So it would be "Does the whole team average X?" as opposed to "Does the weakest individual hit bar X?"
It sounds like the interview process is still mostly individual (emphasis mine):
> Once you’ve applied, we’ll take you all through the hiring process together: we’ll make sure you hit the same stages of interviews at the same time, bring you all to the office on the same day, and try to design at least one interview problem that you can work on as a team.
If we make an offer, we’ll make it to all of you, at the same time; you’d all be free to accept or decline individually, but of course we’d hope you’d all accept
This implies individual hiring criteria. It's interesting that they let the group try and solve a problem as a team.
I wonder how this will impact compensation and offer acceptances.