How long until team registration deadlines are up?

See above, April 27. We are definitely registered already

Or is there a deadline on project selection instead?

Also April 27. I've talked with SETI.Germany guys and I can still email the projects. I didn't want to select the projects on individual preference, but team-wide decision, so the question above for a1) - a4).
Anyways, the wishes of ALL participating teams are weighted, so our project wishes may not be the final list in the Pentathlon. But I think also we can use this opportunity for internal polls ;-)