For the love of god do this: https://www.optoutprescreen.com/?rf=t
We had all sorts of zombie debt (none valid) pop up when we applied for our last mortgage. Made sure to opt out this time and not a peep from anywhere.
If you are past the SOL, I personally say let bygones be bygones. Don't contact anyone and certainly don't notify your lender. You're not legally obligated to do so, and you have suffered through the mandated period already.