2) Allow more quotas in waiting list. I guess 10 is not enough. There should be no extra effort if they are kept in a "don't care" status. And maybe someone else would step-up to arrange another BB party if there are many in the waiting list.
3) Advise the new member to just post their own name as registration, no need to quote other's to avoid confusion on May 1 morning. And then someone later to do the consolidation, may be by May 1 noon.