Isaac,
The one thing I can think of in my
experience with Bat houses, (I am only talking about Little Brown Bats that used my houses). The bats seemed pretty skittish about the houses they would decide to establish themselves into. The beekeeping activity under them on the bee hut floor might reverberate through the posts into the houses. Any banging, thumping, or shaking going on in the bee hut, would (in my limited experience) disturb them
enough to keep them from using the houses. I say give bat houses a try for sure, just put them up on separate posts, but then that would kinda defeat the saving material idea.