Nothing currently exists to help migrate DBs. Not yet anyway (other Lemmy admins have also expressed an interest in changing over).

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.