I don't think that he's ground crew because he is also wearing a parachute harness. The two guys with the bus-driver hats are definitely officers, the rest are unknown. Cunt caps are issued to both enlisted and officers, and were then as well. The Army was pretty loose with aircrews on uniforms, which makes it difficult today to be able to determine things at first glance. I am still thinking a two-seater because there are three guys with radio headsets on.
But then, could be a radio op/bombardier briefing, or they could all be radio operators. Could be partial crews from multiple aircraft. I think we need to look at the gear and the gear doors.