I don't see what the advantage of the middle one would be, but I really like it! It has a Crimson Skies feel to it.
The advantage would be: testing the twin-boom layout (intended for the final pusher step) without having yet the tools to manufacture a brand new fuselage/pod. Maybe.
But you are right, Logan, this seems not plausible a story. So I must reveal the 'Real' one
: the proposed twin-engined P-40 was a push-pull twin-boom aircraft, inspired by the Fokker D-XXIII, but the test pilots refused to fly it (in case of bailing out) so the rear propeller was moved ahead. No?