I doubt AA will book you on QR... AY might be a option... I know that have a DEF to HEL flight..
best you tell AA what you are looking for rather then leaving it AA...
I have a AA/BA flight on the 26Th thru LHR with a onward flight.. going to wait to see what happens in a day or two..
the action at LHR should not affect those in transit... but LHR has been asking airlines to limit passengers flow