I've got DFW-ORD-HND booked with the TPAC flight in JL J

I've got a slight concern about the 1h23m connection time, and I see space is available via BA for the flight an hour earlier. Based on this thread I think I can call and change my domestic connection to the earlier flight, but my question is what is the risk of losing the JAL flight? Would suck to lose the whole itinerary just because I am a bit concerned of the connection time.

Also ill add a very dumb question but my bags can be thru checked right? (sorry I never ever fly with checked bags but need to this time)