If you were able to buy 2 duplexes as replacements then you would own MORE property so that any market appreciation is magnified and you might have MORE loan principle to pay down further building wealth that you don't see just by looking at cash-flow. 

Buying a multifamily property is essentially buying a business—income minus expenses.

Agreed, in principle.

From your post you are seeking to essentially knock down the house and build brand new.

The seller sets the price higher than market price and between the down payment and any monthly principle payments the price eventually gets down to market price by the time the tenant could potentially buy the house.

@Isadore NelsonYour plan's financial analysis includes $48,000 mortgage payments, about $229 in monthly principle and interest, $200 in taxes and insurance, and $950 in rental revenue.

Do you have access to private equity investors or/and key principles and co-sponsors with a track record?

But.......I just don't like the whole principle of the thing.

It's also essential to understand local regulations regarding short-term rentals, as they can be strict.

Must be occupied within 60 days of purchase, and must be considered the principle residence.