Facebook has servers all over the world; there's not just one Facebook server although it appears to users like that. What would be the effect of asking (potential) Facebook users which server they would like to join?
In a somewhat related question, does anyone know how the extra-instance account transfer request is going? Not sure where to look to find out.
Content cannot be and probably never will. Even Mastodon doesn't allow it:
Mastodon currently does not support importing posts or media due to technical limitations, but your archive can be viewed by any software that understands how to parse Activity Streams 2.0 documents.