Yes, you cannot waitlist before you can book. (Although there is a possible 13 month lottery clause for home resort owners for possible holiday periods in the contracts....) WL's should be first come, first served, but the entire waitlist must be available before it can be granted.
So it may be possible that 1 member first waitlists for 7 full days, then a 2nd member w/l's for only 2 days and the 2nd member gets their w/l granted before member 1.... I think if you can book any days, book them, then w/l for the rest..