I just flew through SFO last week 10pm arrival (CX872 -> AA1522 to ORD). 75 mins with checked bags is too tight, only because of the need to pick up your bags, go through customs, then re-check. Go with the ORD connection.

You will need to haul your bags to T2 (exit customs, turn left, and avoid the tram like malcomkettering mentioned) and re-check at the AA counter. The first class line may be closed, but since AA has 3 red-eyes (ORD, BOS and NYC) they'll have one decently-staffed line for everyone.