1- very good idea and analyse
2- teams of 7 would be ideal imho
3- to ensure a minimal participation, it can be started as a semi-automated event by gms, and when the population gets larger, I don't know, something like 400+, be an automated event helded like 2 or 3 times per day (or per week) at specific hours.??
I'm sure this is the kind of stuff that will interest a lot of people and that will generate less whining than pvp events.??
If this is well implemented, I'm almost sure alot people will get addicted.??