Just a few questions

[DanDrobates]

Generally it’s difficult to sex individuals until they reach adulthood. You may find sexed pairs available through online vendors occasionally but your post said you’re not interested in breeding. In that case start off with two juveniles and hope they’re not a pair. The more frogs you get the higher the odds of getting a pair. If you’re concerned about unwanted breeding do be advised that Leucs tend to breed more sporadically than other species so the likelihood of getting tadpoles is less than a species like epidobates Anthonyi which breed like rabbits. Also, it’s unadvisable to mix morphs as they do represent wild locales and lineages any any accidental breeding will dilute that particular lines genetics.

[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.