I think your cash flow is low for 5 SFR, but the 15-year mortgage is a smart play. The

The obvious problem as a landlord ecosystem is that cash for keys usually doesn't exist on an eviction database, so the same tenants can play the system and consistently rip off landlords.  

But you may put your new property under contract at any time before you consummate the sale.This also brings into play the idea of using contingencies on both sides to give yourself some breathing room.Most of our clients purchasing larger properties will always attempt to complete as a regular exchange but they will keep a reverse exchange in their back pocket in case they have to close the new property before the old property or properties sell.  

Some syndicators play the game the wrong way. 

Do you buy one or two properties - then play the waiting game till those two props throw off enough yield to go after another asset.

if you can afford to lose $ on it month to month and play the appreciation hold... then yes.if you are paying cash.... then yes. 

Low end rents that aren't on disability have seen higher numbers of people trying to play the system.

To your last paragraph: I always play the mental game of whether burning the ships is what will set the fire in motion.

Your track record for how you're managing your current properties will definitely come into play. The

Also, the Housing Authorities who participate in Section 8 have New Landlord Training Classes (in some communities it is a requirement of new landlords) - and I recommend you take it online so you can know who the players are and how they play the game.