I'm going to keep this method in mind when my children are ready to leave the nest.

My goal is to create cash flow and gain financial independence to where I can leave my full-time job.

You shouldn't be talking about leaving your first real job as an adult already, that's a Lamborghini hope with a Yugo foundation.

Second would be leave the paid off one's alone and use them as a financial base and security.

Alternatively you can invest in better neighborhoods, perhaps be forced to leave some of your cash in the real estate but experience meaningful appreciation or if you choose to sell, be able to turn the forced appreciation into cash in your bank account.

What are pros and cons of leaving LLC address as is vs updating it to my new PO BOX.  

Other people simply do things completely wrong and that "doing it wrong" is commonly labeled as "normal" or the norm.Listen to the data, leave emotion out of it, and crush it!

All in cost ~750k, revenue possible at 90% SS and 60% parking roughly 175, operating expenses on the conservative side of 50k leaves 125 for P&I and profit.

As others have mentioned above, the first lien might have a large payoff leaving you with little to no equity. 

I would like to eventually leave my 9-5, pay off student loans and get rid of PMI on my first property ASAP.The townhome is my primary residence and I will answer any questions and be grateful for any guidance.