Unlike the P-61, the P-38M never deployed overseas. All of them were delivered to the 484th Night Fighter Group, which was still working up at Fresno when the war ended.
P-61s were extremely effective in the ETO, where they were saw extensive use train busting at night (the only time trains could previously run in relative safety).
While we no longer have night time in AH2, the P-61 would still be very effective. Think of it as an A-20 on steroids. It would out-turn an F6F and out-climb a P-47D-11. The P-61B could haul up to 6,400 lb of bombs and rockets. I'd fly it. In fact, it would be the best GV buster in the game.
My regards,
Widewing