You'll have access to the Admirals Club in Terminal A where all AA flights depart BA uses a contract lounge in Terminal D, but it believe it is departure only.
there is also a centurion lounge in Terminal D if you have access via Amex.
Regardless, with 2.5 hours, clear immigration and customs, go through security and head to Terminal A.
An advance welcome to the one of the most disappointing major airports in the US.