By law they Do have to give you a Pay Off, though they usually drag their feet. 

If that is the best route to take, do I turn around and buy a third property with the extra cash?

As it pertains to the two units downstairs that I usually rent on a long term basis, I've come to the conclusion per guidelines I've read from FHA that they don't care as long as the risk of me AirBnb'ing my own primary residence isn't there. 

Could park those on the open ground, but no climate control...also a big thing for people with extra $$$ to spend storing forever.Know thy customer!

As you probably know already, they have to pass Act 34/114/151 clearances, usually annually.

I don't think it would be easy to add on an extra "expense" like that and expect your tenants to pay it.

This number is going to be different across every market, asset type, and lender, but it's something that each lender should provide in their initial preliminary quote, and in most cases is negotiable.I'll usually ballpark reserves at ~$250/unit for stabilized multifamily. 

Usually they offer a "haves / wants" time during the meeting.

But maybe you get an extra 5-10k on the HELOC which allows you to get in on another deal.

I even paid for the extra HVAC coverage.