I have a few flights coming up in September which I’m a bit worried about...

Sep 4 CBR-PDX
QF704 [booked as AA7398]
QF11
AS565 [booked as QF4113]

Since I’m on the AA code for the first sector, I don’t think I’ll be able to use online checkin. Will the check in agent check me through to PDX, or will I need to recheck with AS when I get to LAX?
I’ll have to collect my bag in customs at LAX. If they check me through to PDX, do I use the bag drop outside customs (ie, the one QF107 uses), or do I need to take it to the other terminal (Bradley > T3) and drop it there?
There is an 8 hour wait between QF11 (arrives 0930) and AS565 (departs 1700). What are my chances of being able to change to QF3785/AS563 (departs 1110)?
The reason I chose QF11 was because of the 388. This flight has since been changed to a 744. Would it be better to see if I can change to AA7390(QF872)/QF107/QF3785(AS563)?


Sep 23 LHR-KUL
QF32
JL721

Will QF check me through to KUL? (There are 11 hours between flights, I plan to head into the city to shop. Would rather not have to worry about my bag).