Both of these allow you to low down payment loans to buy a primary residence with fixed interest rates.

Can someone explain something about the buy, borrow, die concept of avoiding income taxes? 

Quote from @Sundone Boutvyseth: Looking to buy a single family home and use as a STR on Airbnb.

We would buy this house all cash. 

House hacking is often promoted as the easiest way to get into real estate—buy a property, rent out part of it, and let tenants cover your mortgage.

I buy houses in the Memphis market.Terry Clothier REI Nation

You’re going to have to buy at least $1M (or whatever you clear after selling costs.), worth of replacement properties, not $500k.

Airbnb is a company so the only way to buy one would be to own stock in the company. 

You are correct, buying a four plex is tricky here putting 3.5% down.

Determine what type of property you want to buy - What Zip code, what condition homes, price range, etc.Contact 3-4 realtors that helped buyer agent buy the type of homes you are looking to buy.Then go with the 1 realtor that you connected with the most.