Yes it exists, but as the above poster mentioned, lots of hoops to jump through.

We've found it's more capable than others when it comes to integrations, reporting capabilities, and efficiencies.The software you've mentioned will be better for the PM activities (property-specific transactions) than keeping up with your financials as a whole. 

Price to rent ratios have skyrocketed everywhere and it's pretty unlikely rent will ever get to a point where it evens back out because at those levels it's just as cheap/cheaper to buy (not to mention most renters can't afford anything like that). 

As others mentioned, if na investment makes sense only from tax perspective, you should not be investing.2.

As @Troy Gandee mentioned use the tax estimator on the County website or call the assessor.

Not to mention that current owners will have taxes go up on their toxic vacant lots due to the cost of buying people out (so sell to us now).

It's a decent tool, but as Greg mentioned, I'd definitely plan for a worst case scenario and make sure it cash flows at the highest interest rate juuuust in case. 

AND there aren't many note buyers who will buy notes with large balances in the range you mention. 

As mentioned.

If you like the idea of a self-directed HSA like @Kaaren Hall mentioned check out providers like Accuplan and IRA Financial Trust.