Property is seen on Zillow as SFH but in actual it is a 4 units.

[Katrina Dividina]

What can we do, I am currently in a contract with this property, it is originally a single-family home and the owner added (3) 1 bed 1bath units at the back (without securing permits). So its a total of 4 unit property now. Its in a small town (20k population) and has no comps. Recently appraised for 240k, I was able to negotiate to 215k with 30k rehab budget (more on cosmetic issues) . My question is, If I refinance after rehab in 6 months, How can I increase the property value aside from renting all units? Is there a way I can inform the zoning to change it to multifamily? (zone is currently mixed use).