What is it that would appeal to the family who is conformably living in a house, undisturbed, that would motivate them to want to sell to you, let alone open probate? 

All conforming loans are going to use the same criteria.

Has the state landlord tenant law changed and your lease was modified to conform to the new law?  

Thus, you'll have to go with the conforming.

Address this at once and, if necessary, serve them with a lease violation notice to conform. 

The biggest issues I see is are you prepared to work out new parking arrangements if you were to build on it.Put it in the contract that the seller obtain a zoning verification letter that states that the existing uses are conforming and to tell you if there have been any variances granted for the properties.

This is where deeds and such are recorded.It is not the same as the property tax assessor/auditor/collector.Many counties have info online but there is not a uniform standard that cities and states conform to.

Refinance into a conforming loan as an owner occupied.

You'll have headaches trying to get this to conform. 

mortgage broker is not going to be able to bend the underwriting guidelines unless you go to a local commercial bank or credit union were they make their own rules.. if your looking for the least expensive debt that is conforming then all brokers fish in the same pond when it comes to underwriting criteria... don't let anyone hit you with pie in the sky ask for money up front promise you the moon then not fund.. lots of that going on right now on BP