If sales price is 400k and I want 75k cash but tenets only can provide 15k, what are my options?

Hey jeremy, sometimes the best options may not be local I recommend asking some qualified investment focused brokers 

I have taken into consideration extra repairs that may be needed due to renters.

Real estate investors have a variety of financing options available to them, depending on their financial situation, investment strategy, and the type of property they're interested in.

., seller financing, lease options, etc.)?

Certain suburbs don't have many options for multifamily, so you might have to open your search to other locations.

I would probably have to return the down payment and option money to the end buyer, and he is probably going to sue me.

You'll likely pay an extra 3.8% on some (or all) of the profit from the Net Investment Income Tax. 

If not, do I have any other options at 20% down? 

This is the 2 units + 2 ADUs scenario.I am worried Scenario A might push future financing option into commercial real estate only, which will limit my cashout refi options and the future buyer pool.From a lending perspective, since a "Land Use Restriction" is required to be recorded on the Deed to limit rentals to be longer than 30 days, the property thus will not be considered a true "5 unit commercial property" and my worries in Scenario A will not come to pass, right?