Hi Dylan
I wouldn’t bother repairng the screwed up system, too many variables, too much risk of being compromised due to the botched migration.
Restore the old running system, and then start a new migration, eg via Backup from the restored VM on Virtualbox to your existing hardware with a freshly installed Nethserver.
If it’s sufficient for you to be able to copy back your data (files & mails) you could do a fresh installation, create your users (as they wore on the old system), and copy over the storage folders in
/var/lib/nethserver/vmail
/var/lib/nethserver/home
/var/lib/nethserver/ibays
to the newly installed server.
After that you’ld need to correct permissions (chown…) on the subfolders, but luckily, on a home system, there aren’t too many users…
This would work… (I’ve also done this before.).
Your mileage may vary, but in any case good luck and no more outages, 'til you’re back up & running!
Sometimes the WAF factor is more important than Hardware… 
(WAF=Wife Acceptancy Factor)
My 2 cents
Andy