The best person to ask your question to would be your bankruptcy attorney assuming you had one regarding your filing. However, if you have been discharged as to your debt by a bankruptcy order, and the deed in lieu of foreclosure and any side agreement that you have with your lender states that you will not be obligated for any shortfall on your loan, then I see no reason for you not to sign the deed in lieu of foreclosure and the estoppel affidavit.However, to be on the safe side, I strongly recommend that you consult with a real estate attorney about the documents you have written about before they are signed and to make sure there is a signed document from the lender that you will have no further obligations to it concerning your loan secured by your home.Good luck.