Definitely not springtails or flies. I have seen springtails in there, and they look very different. And I have seen fly larvae (not in there) which are also very different. If I did ever put a trap inside it would be with a natural thing like vinegar or something to attract them, nothing hazardous.

As for the dry look, it was towards the end of a misting cycle (I do it in morning and evening typically), but my humidity stays around 90% for the most part, and even goes up to 94% occasionally. I assure you it's quite wet in there, I just don't spray the glass very much. During the day it does fog up though, but opening it helps it to clear pretty quickly, and I generally wipe the front one on occasion just so I can see.

Oh and screen top.... I have glass over it, and I know it might eventually rust, but it's not on my immediate to do list. I am just keeping a close eye on it for now and so far no signs of rusting any time soon. Probably because I don't spray it or anything... so it will take longer from the humidity alone.