I definitely imagine some flocking n migrating, yeah ofc ofc. A bit of a diaspora? But a lot of moving back and forth, too. Maybe a lot of L'kor will leave the planets they went to because the springs on Naiva are too good to not be there for, like IRL birds? btw easiest way to spell their homeworld is avian backwards, we're leaning into the joke here canonically guys.
You can play a L'kor anytime you want. As a GM they are a part of your tool kit to do that with. You could make NPCs for yourself, etc. The baba yaga used them sooo so so much, so do it!
If there is considerable interest in having them as player characters I'm okay with the L'kor being opened to them with work, but I'd only do it if the cost to benefit ratio is there.