40 minutes is legal and doable, but not without risk. I'd go for stand by earlier and get a longer layover in ORD. If you miss the conenction - you'll wait a minimum of 24 hours to get out on the next AA non-stop, or could get lucky with a reroute via LHR on AA/BA.

As for J seats and service - check the unnofficial guide stickie for direct links to threads in international J service. It's been discussed and rhased here many times over.