Next month I'm booked on BA297 LHR-ORD connecting to AA1651 to SEA. Connecting time at ORD is 1:56 but BA297 appears often to arrive late (< 30 min). Will this connection work if BA297 is running up to 30 min late? (I don't have check-in luggage and I'm in J class).

There is only 1 later SEA flight but that is on UA. AA will rebook me on their flight the next morning if I miss the SEA flight (and pay for hotel) or the UA flight?

Is there any chance that BA would accept me on the direct LHR-SEA service which departs 35 min earlier than BA297 to ORD, if I inquire at LHR?

Sorry, for these questions but I'm concerned that I will not make it to SEA as scheduled as I have been to ORD before with very long lines to US immigration.