If the guys want colour in the woods, I think I'd give them colour in the woods. Work within those constraints and spend time scouting a few good locations and thinking about how to make it good. Regular clothes is a bit of a disappointment, could be difficult to make it interesting and not just 'group of men in woods'.

I'd toy with the idea of getting them to set up a full-set in a woodland clearing. Drum kit, amps, everything. I'd then get as many people as possible to turn up and shoot the band 'playing' live so to speak from a slight distance as if you were three rows back at a gig. So, some dark and blurred back of heads in the shots but the focus on the band. Would be great if you found a clearing where the light illuminated the area but left the surrounding woodland in relative darkness.