Correct, there does not appear to be a definitive road marker (or case law ruling that I can find) yet on this issue [SOL]. (I don't mind the prospect of being a trailblazer; being the first to bring and prevail on the argument. Though, I can't likely foresee this matter making it that far up the chain.) That said, considering that 'the state' is doing everything within their power to 'constrain' a tax auction purchaser's rights after sale, not 'expand' their rights, that fact works in my favor.
Yes, I was the homeowner. And correct, my right of possession extended through the redemption period - which in Michigan was:
"fee simple title to property foreclosed by the judgment will vest absolutely in the foreclosing governmental unit, except as otherwise provided in subdivisions (c) and (e), without any further rights of redemption, if all forfeited delinquent taxes, interest, penalties, and fees,... are not paid ... within 21 days of the entry of a judgment foreclosing the property [in a contested case]"
But, yes, I am outside of the 10 years, or '21 days plus 10 years'.
This situation makes my occupation of the property a "holdover tenancy" - in which case:
a) It is "understandable" (in the eyes of the court) that I still possess the property;
b) But, that does not give me a 'legal right' to still possess the property;
c) However, not having a 'legal right to possess the property' does not make it 'illegal' to possess the property (wherein they could haul me off to jail). I simply have no rights to the property and the typical resolution, as you likely know, is that the new tax auction purchaser goes to court to have the court "authorize" the use of the sheriff's powers to remove (evict) the holdover tenant.
That said, and this is also to my favor, the state did eventually start to include notice in their policy outline that "after foreclosure the previous owner has to vacate the property".
NOTE: Just for reference for any future readers of this post, Case Western Reserve Law Review published a legal note pertaining to this very issue of tax foreclosure post-sale failures: "Interrupting the Blight Cycle: Managing the Future of Properties in Tax Foreclosure Sales Through Pre- and Post-Sale Initiatives" (Ellen Kirtner)

