Here are my thoughts.

1) Yes, and they clear First in First out PA first then PB
2) These waitlists are only in effect UNTIL passing to airport control On Checkin, pax on the waitlists are transferred to the DM list which then clears by Status, Fare Class and time added
3) Yes
4) Depends which waitlist they are added to. Unless the mileage upgrader is a 1K or GS, the answer would normally be yes. Otherwise, it depends when they are added as it clears first in first out.
5) Prior to DM list it is FIFO, then the DM list clears by Status, then Fare Class and then time added.
6) I haven't been able to, but apparently it is possible to do based on somethign I've read here in the past.