I will most likely have to list the flip right now and sell it 90-95% completed and take some sort of loss. 

My father in-law verbally and immediately agreed without any sort of paperwork, etc.

That can be a problem with larger companies.

Or even that doesn't include property tax but does offer a GRM comparison and allows to sort that way?

When dealing with the banks they want to ensure that you have plenty of reserves sitting in the some sort of money market, whether it be 401k, savings/checking, stocks, etc.

I plan to house hack a multi-family of some sort. 

It is more of a (right sizing) of existing medium to larger box size tenants expanding their online footprint to maximize omni-channel marketing to get the right optimal business ratio to drive sales and profit margins.    

The larger national footprint firms will be able to give you good economies of scale but your experience will still be limited to the quality of your assigned representative. 

If truly all it needs is a new roof to be complete and ready to sell then a few ideas off the top of my head could be:1)  Borrow the money from friends or family to replace the roof2)  Put the cost of the roof on a no/low interest credit card and pay it off as soon as the house sells3)  Go through a home improvement store (like Home Depot) that offers financing for larger projects like roof replacement4)  Don't replace the roof and just lower your sales price or offer the buyers a credit to fix it themselves after closing

In no case may an accessory dwelling unit be larger than 30% of the primary dwelling unit, or be permitted where inadequate infrastructure exists.