Dear Jeff,
Looks like you have found the problem, But how are you planing to remove the server from domain and add it back.
It would require downtime...!!!
Why not make a local system user with administrator privileges and uninstall the named instance using it. Later on you can add this activity to your list of planned activities.
Regards
Shafat Husain
Regards,
Shafat Husain
🙂
And Your Lord Never Forgets...!! (64:19 -- Quran)