I acquired this property with a 20% down payment and an 80% seller financing note with a 2-year balloon to allow myself enough time to stabilize it and get longer-term commercial debt on it.Over the last 7 months, I was able to raise the other 4 units to market rent and lease out the larger 5th unit to another state government agency on a multiyear lease.

I have enough cash to put 20% down but this only allows me to purchase a home that's cheaper than my current one (even after counting my current home as rental). 

It allows you to buy a property with a smaller down payment since you'll be living in it as your primary residence.

Hi Bauclair,I'm assuming you have an inspection contingency clause that allows you to back out of the contract?

It is always best practice to use the state regulated forms, although it is up to your Broker on what forms they allow agents to use. 

If you strategy is to build a rental portfolio as fast as you can then, you want to refinance at the highest available leverage. (75%) That allows you to preserve your capital so you have down payment money for your next deal.

There are currently only two areas that allow STRs.

Although, you're not going to find much under $100k that allows STR.

Additional information: rZoning permit from 1/16/1956 with a variance granting this as a 3 family unitI have no building permit saying this allows this as a 3 familyI am asking for any advice specifically for Philadelphia, PA.

This would allow me to have smaller payments on my primary residence.