As per the title.
If I was running a Vanilla forum and wanted to migrate over to a new lemmy instance, e.g. forum.com to lemmy.forum.com Could I migrate the entire forum over while keeping the same categories/sub categories as communities I guess, and bringing all of the old threads with them? If it is possible, would it be difficult?
Seconding the piefed recommendation. It’s much lighter to host than Lemmy, and has some nice user facing features that Lemmy lacks, which you can read more about here (scroll down to comments):
https://slrpnk.net/post/24141955/16757434