Beautiful banana! He looks so sweet and gentle. He is so lucky and spoiled with that lovely enclosureIt's really nice that he's a good eater and growing fast, he looked a tad skinny in the original post but he filled out nicely very quickly under your care.
For the humidity, I'm not sure if Reptibark is the same as Forest Floor cypress mulch in the sense that it is super damp when it comes out of the bag, but if so, what I've found helps is spreading it out in another container or a large plastic bag and letting it air dry for a few days before putting it into the enclosure.