Nothing currently exists to help migrate DBs. Not yet anyway (other Lemmy admins have also expressed an interest in changing over).
I noticed though how easy it is to replay activitypub events in pyfedi - i used this once to recreate a deleted posts along with all of its comments and up/downvotes on my instance.
If a lemmy instance somehow had all of its server logs preserved, it might not be too difficult to craft them into replayable events for pyfedi, allowing all the posts and comments and votes to get recreated. It’s of limited utility (most lemmy servers would have rorated aways most of their logs long ago) but still an interesting thing to try out…
No, sorry.
I’m not sure if you mean migrate an entire instance to PieFed or just move your account?
In Lemmy you can export your settings, which includes a list of all the communities you’re following and then import that into your new PieFed account. But you can’t bring your posts & comments with you.
Migrating a whole Lemmy instance might be possible one day.
