In the worst case, I may need to keep the property empty (while paying more than $4000 mortgage each month) until next Spring. 

I do not know the layout, but believe 5 units is the worst unit count.  

The worst. 

My only backup plan if I can't get verified funds is to assume the worst and to drop my counter offer even lower than my original due to the risk I would be taking on, and then when I do my in person inspection try and guess what rents are fair market for the empty units, and ask as many tenants as I can what they pay in rents monthly.

Verifying last 2 years of rental history and income extremely important to find the “best of the worst”.

Worst case, you might have to pay off the second loan to streamline the process.Your plan of using private money to take out the hard money loan and structuring seller financing for the rest could work, but just make sure you’re crystal clear on the terms with the seller, especially if he’s staying in the house.

Verifying last 2 years of rental history and income extremely important to find the “best of the worst”.Make sure you understand the Class of properties you are looking at and the corresponding results to expect.The City of Detroit has 183 Neighborhoods we’ve analyzed.PM us if you’d like to discuss this logical approach in greater detail!

Best case scenario - it goes as originally planned, but at least you did your underwriting based on the worst case scenario2.

The WORST solution is an unqualified attorney, because their mistakes makes whatever they come up with INFERIOR to an “off the shelf” solution.In between the two we have a good off the shelf product by a reputable vendor.  

Budget for the worst and buy low accordingly.