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.

The major Star Trek subs all have. Started their own Lemmy instance (startrek.website) and have their private message directing folks over.