I have been looking at the Matrix and it seems you can flight non-stop on AA MIA-BCN on the 16th and back BCN-JFK on the 23rd for $ 2489 per person. Assuming that you can get OMA-MIA and JFK-OMA for a reasonable price I think that's an option.

With your original options I would pick the ones that go through MAD, to me a much better connection than LHR with its annoying lines (and I think that even the Schengen lounge in MAD is better than the J lounges in LHR).