Generally you won’t see microfauna unless you dig around in the substrate. It’s always wise to keep a few starter cultures for future seedings. If you have a good substrate and match the species to the environment they’ll do well and you’ll never know they’re in there. For high humidity dwarf white isopods and temperate springtails will do well. As far as substrate goes use a drainage layer of gravel or leca, a barrier such as vinyl window screen to keep the substrate out of the drainage layer. Then add a mix of horticultural charcoal, spagnum moss coco coir and cypress bark. Top it off with leaf litter such as magnolia or live oak. This will give your microfauna a perfect place to thrive.