Originally Posted by dstan

1) Yes, if you book the codeshare AA flight numbers, they will count
2) - I'll have to leave this one for someone else to answer -
3) You should receive bonus miles for the flight on which you cross the EQP threshold for finishing the Challenge
4) Yes, but it's based on the Challenge start date, not the flight dates per se.
5) Yes, you can apply flights toward a Challenge after booking (but not after flying)
6) You only start accruing MTEU (miles toward elite upgrades) once you achieve status, i.e.: complete the Challenge.