That tank looks awesome, good job!
I would wait a few weeks, although it isn't the end of the world if you don't. The wait will help the plants and springtails establish. I'd definitely feed the springtails so their population grows before adding the frogs.

All that said, I very frequently plant cages the day I add frogs. I definitely don't recommend that though.

I think leucs are an awesome choice for that tank. 2 is probably a good number, but you may be able to do more than that. I keep 3 in a 10 gallon and they're doing fine. However, you would definitely want to keep an eye out for aggression and make sure that all of them are staying healthy.
Plus, unlike some darts, leucs are so active that you'll always see the them, thus eliminating the need for extras.


I think I just talked myself in a circle! The tank is awesome and i'm sure the frogs you get will do great in it!

~Alex