I'm a contractor, I have a signed contract to assist in rebuilding a residence after a fire. The contract was signed in May, The city signed off on the CFO in August. The homeowner who is/was a friend was going to refinance and pay me. I know the dates are past 90 days but i was wondering if I had the homeowner sign a new contract if that would satisfy the criteria for a mechanics lien or should i try another route
The short answer to your question is No.
Michigan's lien statute requires a construction lien to be recorded within 90 days after the lien claimant's last furnishing of labor or material for the improvement, under the lien claimant's contract.
The issue you're grappling with isn't the date of your contract, but rather your last date of work. If the work you contracted for is complete and the City has issued the Certificate of Occupancy, signing a new contract would revive your lien rights. Unless your friend also intends for you to perform additional work in which case a new contract or change order to the existing contract, PLUS furnishing additional labor and/or materials might help you out.
But rather than trying to manipulate the last date of work so you can record a construction lien, I would ask your friend to acknowledge the debt he owes you and sign a promissory note. The note can provide for installment payments or a lump sum payment once your friend refinances the house. A promissory note can also include interest.