I would be cautious too if I were a sub owner and guiding people to an alternative honestly. Lemmy and Kbin both are relatively unstable right now, even if they are pretty good. Waiting a little to see which instances are more stable and likely to last is a good move before planting people somewhere and making an official replacement sub.
Well, on Beehaw you cannot create new communities, but you certainly can be made a mod of one even from another instance. Find the ones you want and ask the current mods of it.