What can I put in here? 12x12x18 exoterra

[Heuchera]

Hey all! I re-set up my 12x12x18 exoterra recently, and am going to work on slowly filling it with plants and vines. However, i'd like the plants and the environment to reflect whatever creature I put in there. I'd like your advice! Are there any beginner frogs that would do well in this size enclosure? I felt like asking individual people rather than looking at online articles would be better, since sometimes articles lie in order to promote buying animals.

The only criteria I am looking for is:

• Beginner species (since I am new to amphibian and reptile care)
• active (either at night or during the day)
• NOT wild caught! (so no easy-to-care-for weird species. My last attempt at keeping a wild-caught frog ended in lots of vet bills and a dead frog. )

Additionally, as far as my substrate/drainage layer goes...is it too deep? Am I constricting the space of the enclosure too much? For reference, it's about 4 1/2 inches from the bottom of the tank - each layer is roughly 2 inches each.

Thank you all. <3