That would get it amended to show as a multi-family and adjust the value accordingly.Hattie

I would keep it and maybe use that incident to try to amend your offer and save a few $k (never hurts to try).

Is there a rider or amendment to the lease that can be signed that says the the rent amount has been changed for the 4 months and everything else remains the same?

And, property taxes are easily offset by the fact there is no state income tax (probably will never be, because it would take an amendment to the state constitution) and franchise taxes are very favorable at .0575% on investments. 

There is a whole thread on this under Creative Strategies - Wrap FHA Mortgage - go read it.Further, if you amend the occupancy of the property to NOO by putting tenants in or renting or messing with the silly Wrap idea, you will screw up any future deal.  

If so, and if you didn't get an amendment extending or modifying the original terms, then I agree with @Richard C. 

Did you have the repair cost agreement on an official amendment form or was it just a verbal agreement?

For the technical idea here, this includes any input or amendment or creation of those documents including kits.  

I buy a lease of off legal zoom and than customize it with all amendments based on experience.

I  have even written indepth about all the process ion my website even all the amendments I would put in a lease!