Both tinctorius and azureus (actually the same species by some standards) are territorial and do best in mated pairs unless the tank is very large. The problem is with the females, so you can keep one female with a couple of males. I would suggest instead that you look into the D. leucomelas, which do great in groups, or if you can afford something more expensive, the D. galactonotus orange or yellow morphs actually do better in groups, and are great, active frogs. The red morphs are more shy. You can also consider any of the D. auratus, which come in a variety of color morphs. In my experience, the blues are shy, but the others get along well and will be in the open a lot. Another thought is the Phylobates terribilis, either the mint or orange forms. These are very bold frogs, and will be in the open most of the time. If you like the thumb nails, D. imitator or its close morph, D. intermedius do well in groups, although they will fight, especially the females during breeding activity. It doesn't seem to harm them, however, as they are very athletic and nimble, and is fun to watch. The gals will mess up and eat each other's eggs, but usually enough survive to watch the full show of raising and feeding the tads.
I belive "Aurora" is a common name for Kananchoe fedtschenkia marginata. The Kananchoe group. They are somewhat succulent and do well in dry conditions, so it probably isn't appropriate for a dart tank where the humidity will be too high and the soil too wet for it. Look into the Pileas, Peperomias, miniature vining Ficus, such as the pumilia varieties, Fittonias, etc. You want plants that won't rot in wet conditions. You can use epiphytic plants if you can put them on something like a cork background. These include some of the smaller epiphytic bromeliads such as the Neoregalias, some Vresias, and you can even get by with some of the jungle cacti, such as the Rhipsalis if you keep them high.
You are correct. The darts don't require UV, and the lighting is for the plants and should reflect that spectrum range. However, you must supplement with D3 in lieu of the UV that will not reach your tank through any glass, along with calcium and vitamins. One of the most recommended combinations is Rep-Cal with D3 and no phosphorus, and Herptivite for the other vitamins. You dust the live insects in this before feeding. Another single formula I like is "Dendrocare." This acquired a bad reputation a few years back when a batch of it was mishandled in distribution, lost its potency, and some people experienced problems. Whatever you use, it must be fresh, as vitamins do deteriorate. Most reptile vitamins have the improper calcium to phosphorus ration for dart frogs, so don't use those.
Good luck. Be sure to post some pictures for us as you build your tank. This is always so much fun to do.
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Patty
Pahsimeroi, Idaho
4 D. auratus blue
6 D. galactonotus pumpkin orange splash back
7 D. imitator
6 D. leucomelas
6 D. pumilio Bastimentos
4 D. fantasticus
6 P. terribilis mint and organe
4 D. reticulatus
4 D. castaneoticus
2 D. azureus
4 P vittatus
2 P. lugubris