so exactly how hard are dart frogs to keep?

[FwoGiZ]

The one big difference with painted frogs vs most other herp animals is that they're not as forgiving as other species...
A gecko can go couple days without water.. or several days without food...
Don't make that mistake with frogs; especially humidity wise.

But if you have all the correct specs and a healthy frog, they're easy!
Some other species are considered hard but what that means is even with all the proper specs and a apparently healthy animal, it might not work for various magical reasons... happens mostly with wc animals but also cb specific species.

I think a 16 tall viv will be too small for a group of leucs... they're medium/large sized frogs.
18x18x24 exo would be a good size for a small group.