well, technically you can evolve every kind of feebas(even them with no hair, boldXD), but some may be hard, and some easy.
If you give your Feebas just the right pokeblocks, it'll also evolve.(I hope)
Hey, this should really be in the thread in the RSE FAQ's section. If you can, please re-ask the question in the thread I'll post below, since this kind of thing belongs in that thread.