That is where you went wrong. You should have run MA during system setup without making any account at all, and MA would have brought the account in.
What happens is when you make an account on a Mac it assigns a userID. The first account is assigned userID 501. So what you did was made account 501 then tried to import from MA another account 501 and this causes all sorts of account and permissions problems. I would erase the drive and reinstall as
@DeltaMac suggested, then after the install when the new install first launches, import from there as part of system setup.
If you want to avoid that and are up for a test... there is another way that might work. Go to users and groups and add two more admin accounts. Name them whatever you want and something different than the other accounts... like test3 and test4. Now login to test4 and delete all the other user accounts and their data. That should get test4 up to userID 504 or so, and hopefully the old account on your backup is 501 or 502. Now from within test4 run MA and import everything. That should bring in the old account and all your data. Once that is done you can reboot to the original, imported account and delete the test accounts.