I think if I were to classify the hybrid species, I would call them 'fraidmares' (which under normal circumstances between a fraid and nethermare isn't possible, but Secret is a special case given she isn't biologically a fraid)

baby fraids can also be called chicks or kits/kittens, and baby nethermares may also be called chicks or nymphs.
Given these two are hybrids, you could call them by any of those names.

It is also funny to think these tiny little things are demi-deities haha

All of the characters I draw are mature + intelligent, unless stated otherwise (with the occasional exception of brain-damage...)