Do I need Ex's Signature on Closing Documents if I have Quit Claim Deed?

The issue is will the title insurance company issuing the title insurance policy for the lender and the title insurance policy for the borrower feel that what you have is sufficient. They will have to payout if later on your Ex-spouse claims that they are still an owner. Will they cover that risk?

When I bought a house about 20 years ago the person selling the house was asked by the insurance company to provide a freshly notarized quit claim deed from the ex-spouse, on top of the paperwork filed with the county. You might be asked to do the same thing.

If they won't sign, or they can't be located, it will depend on what other paperwork they will accept.