Now to the "DUH" factor; who's paying this ADDITIONAL $25k per FTHB money?

Not so much with the letter but I'd have them fill out any additional info you need when you have them fill out the tenant estoppel form during escrow.

In addition to the rentals we would always do a live in flip on our houses and have moved about every 2 years for the past 10 years. 

Recently came across a few good within my budget properties and do not want to lose the opportunity to invest and wondering how to go about the loans since I am not employed anymore and the lenders that I was working with for previous properties always ask me for employment verification and 90 days' pay slip.

If there are excess funds after paying the local/school real estate tax bill, the remainder can go to:Current real estate taxesCurrent Muncipal liens for water/sewer or any other bill initiated by the municipalityState Liens, usually for outstanding state taxes, sometimes employee/employer taxesPA State Inheritance Tax which applies to all deceased owners and starts at dollar one with no exemptions, unlike the Federal Estate Tax. 

If its positive it adds to your job/self employment income as a total income figure to determine your DTI or debt to income. 

Live in one unit , rent out other unit and accessory unit, mortgage on the property would be about $6800, rental income would be : $3000 from additional unit , and $1500 from accessory unit and I would be occupying one unit , leaving me at negative $2300 per month .

If a tenant is not placed before November, I fear you will have additional challenges renting the unit which likely will not improve until March.  

They might give you a discount to add it.

Would also be curious to know about some of the additional tech stack to consider, as I am sure there are gaps in each of these platforms for handling specific scenarios. 1) I’ve been curious about how other property managers handle tenant retention, especially as portfolios grow.