Personally I'd get rid of the sphagnum moss, There's a risk of the sals eating it and becoming impacted. Eco earth/coco-fibre soil is what I would use, live moss is okay as it is rooted and isn't as easily ingested. you can get some nice pillow and sheet moss on www.dartfrog.co.uk that looks the part as well.
The underground basement hide sounds good and they'll love hiding under the bark. Welcome to the forum by the way!
I agree, replace the sphagnum. I use composted bark soil improver in almost all of my terrestrial set ups, cover this in places with moss you have collected from a pesticide free place and rinsed well, There is always the kitchem paper method, which I have used with good results with fire sals. Bounty[plenty] is good for this as it is strong and very absorbant.