Green Tree Frog questions

[DanDrobates]

I’d strongly advise against mixing the two species.
1. American green treefrogs are by and large wild caught and you could bring unwanted parasites and disease into your established terrarium.
2. Whites (Litorea caerulea) are much larger and could stress or even prey upon a full grown American green (Hyla cinerea).

As far as substrate coco fiber is fine but provide a feeding cup to lessen the risk of impaction.
Their call can be loud but that’s part of the fun.