(not so important but if they only require 15% down on a single family home that is usually a good sign that you are working with a flexible lender) Can I change title to my LLC?

Worth to check them out,They usually have higher interest.  

They usually have products like that. 

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

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. 

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

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.

An estoppel agreement for the tenants is voluntary, and usually not needed.

As @Anthony Wick pointed out, the landlord usually has to mitigate the loss by attempting to find another tenant.