How can you obtain the other Kana?It unlocks the paralouge as soon as you start it up but unless you have the mother they will have the hair colors that they have in the Heirs of Fate DLC. I also don't know if getting them before actually getting there mother affects there stats in any way, though it probably doesnt. It works just fine for Corrin.
By the way you can also obtain both Kana's with full supports.