I know not Linux BUT I must say the most important thing here is the database. That will have ALL your edits/manual changes. Just get a hold of the db file. Everything else(if not backed up/restored) is just a sit and wait till everything gets re-scanned and metadata downloaded.
Just remember, the information in your plex database isn’t/doesn’t use relative paths for media and metadata. Be SURE you put all media(use same paths as before) if you reinstall the OS and add everything back.
Oh yeah, one important note. Always COPY the backup db to the new install. That way if it all goes south you still have a copy of the original db.
Good luck!
