With four plex you have to pay utilities for the hallway and common areas, also maintain and clean the common areas, because the tenants won''t.

What kind of loans are best for this?

They don't care about your criteria, since it's not going to change the kind of deals that they come across.The take-away here is not to be like most newbie wholesalers: Don't do "carpet-bomb" marketing!

That depends on how many units are in your MF, what your longer term goals are and what kind of lifestyle you want.If there are a lot of units or you plan to have a lot of units in the future then invest in setting up good systems now.

So make sure your uses of the refinance money conform to business  purposew if you want to write off the interest.This method is commonly used in a 1031 consolidation exchange. 

Settling is common and you often don't do anything with older properties unless the foundation walls are coming in. 

This is very common so don't feel discouraged by maybe having to do some "inner work" or whatever you want to call it.Hope this helps!

It depends on what kind of income he has.

Quote from @Bryant Brislin: Land in the path of development that may seem a little far out, but your gut/intution and common sense from an urban planning perspective tells you that some day, whether it's in 10 years, 20 years, etc it will be a great long-term position for your family to have and hopefully sell at a signifcant multiple return compared to what you've paid for it.

From purely a lending perspective, the projections from AirDNA and Rabbu are the only commonly accepted sources for underwriting a short term rental purchase or refinance DSCR loan.