the way i see it, they are in winter gear. They don't look to much japanese. they look more like starship troopers.
In any event, the game has anime influences. I'm no anime fan either, but in the book "the Art of Halo" the originaly maste rchief was anime based. alot of it is influenced by the japanese style of things, although the finished product of halo came out unique.
I didn't really see to much of a japanese influnece at all though. This is also supposed to be in the past, so maybe things looked more japanese back then.
the music didn't really sound asian either. i actually thought it sounded more middle eastern on the part when the elite held up the dead marine.