Well, I'm certain I don't want to pay BA fuel charges, so I won't be taking a BA flight, which leaves AA then. Can I fly all-AA and book as a Oneworld partner? (I guess that even if they wouldn't let me, I could book a dummy leg, right?)

Are you saying the only 3-cabin first class AA flights from the whole US to Europe are flights to LHR, or that the only first class flights from MIA to Europe are through LHR?

Also, the AA route map shows MIA -> BCN (with Iberia). But, a kayak search shows 0 direct flights from MIA to BCN after like 20 searches. Is the route map wrong?

Thanks again.