Just a few questions

[JimO]

Leucomelas are one species of the larger dart frogs that does well in groups, especially when they grow up together. You would likely do best to pick up four juveniles because it is not uncommon to lose one in four. If you aren't breeding, then you certainly can keep individuals from the different locales together. Most leucomelas bloodlines are not pure anyway. Regarding breeding, if you don't have a place for them to lay eggs or water in which to drop the tadpoles, you don't need to be concerned about caring for the young. Without a damp surface on which to lay the eggs, they either won't be fertilized or they won't develop. I know it sounds kind of cruel, but if there is no water feature in the enclosure, then the tadpoles won't survive even if they do develop.

Josh's Frogs carries several different leucomela morphs and they give discounts on "4-packs". They might be willing to mix them up in a single 4-pack.