My first frogs were a trio of RETFS. They aren't that hard to keep especially in HK which is always quite warm and high humidity here. None of mine have died since I got them in 2013.

My other set of frogs are milk frogs.

So I think you are fine with keeping RETFS as your first frogs. As I just use paper towels in a 20 gallon tank and my set up is not complicated at all. They are so visually striking and nice to watch at night! My milk frogs are in exo terra 30 gallon 18 x 18 x 24. If you have 4 RETFS, I would recommend getting that exo terra.