I think it is important to know what the temperatures and humidity values are before naming all species

In my opinion, best starter frogs among the Dendrobatidae are the ones that will forgive you some mistakes, wich you'll definetely make in the beginning.
D.leucomelas is capable of handling a wide variaty of temperatures for example, but doesn't go that well in a group with multiple females, if you like to breed them chances are you'll never see any clutches before aten by other females.

Another species, Epipedobates anthonyi (used to be tricolor)
In Holland THE beginners frog, because their boldness, easy to breed nature, doing well in a group, handling a wide variaty of conditions and making quit some sound.