The 10-year Statute of Limitations doesn't apply if you willfully failed to file a tax return. The clock starts ticking on the later of the date of an IRS assessment or when the tax return is filed. 11 years of back taxes are rightfully owed here.

More importantly, how do you feel about it?

To me it looks fine.

and did you ever follow up with your roommate to ensure it was closed/transferred?

I think I know where the mix-up occurred