Negotiated with sellers agent back and forth for a week and seller accepted my offer How did you finance this deal?

I agree with @Aaron Zimmerman—setting up your chart of accounts to align with Schedule E/1040 or 1065, depending on your type of entity, will again take some of the heavy lifting come tax time.

Certain lenders can accept higher than 50%, and may be able to execute even with an exception. 

However, my portfolio is mostly B2B and the businesses I work with are comfortable paying the nonrefundable fee plus the refundable security deposit. 

And to his credit, Federal Reserve Chair Jerome Powell seems in no rush to cut rates with inflation above target level.

Not a good one to go with.

The property is worth exactly what it is with zero STR rental income.

In PA, IRS liens will have a 120 day right of redemption with a mortgage foreclosure (and with a judicial tax sale as well).

I'm not sure I would get to cute trying to squeeze every time out of it now with a lease that might cause you issues in the future, but the scenario you describe is common and probably smart. 

I think that it is a good long term investment with some serious upside, but don't kid yourself - your car (or your tenant's car) will likely get broken into at some point.