Themes would be my start, but that would require the instance owners to add them once created.

Are you talking about a docker setup? if so, yes, as long as you update your bind mount to the new location. If manual install, I would think that you'd have to either leave it in place or find what references that location and update it as well.

yup.

Good question! I don't know.

Being able to comment on this chain from my own instance of lemmy is really cool. Beehaw looks to have many good communities, will definitely be hanging out here, even as a non-user on the site.