You are in a really good position with that amount of cash. 

I just started to cash flow positive last year after all my mortgages were paid off, but I have made multiple millions in appreciation.

You could refinance out of the 203k and take cash out assuming the equity position is there at the end.  

Therefore, I believe I should be in a position to leverage up my balance sheet, grow my real estate portfolio and generate more passive income.

They make a little over 3x rent, have a small dog, and had positive reviews from prior landlords.

I am not eligible for a conventional loan as I am working for a start-up company and will not be approved for a mortgage.My thinking is to seek owner financing,negotiate mortgage directly with owner, and put up to 50k down for first property.Am I going in the right direction seeking financing directly with owner or do I have any other options in my current position?

I am interested in buying a cash flow positive SFH or Duplex rental property to get started.   

I discovered bigger pockets, bought some books and I began buying rentals.Without providing a long drawn out explanation of my positions, just know that I have three 4 unit buildings now, a total of 12 units, all excellent deals, all cash flowing.

The OP can have the prospective tenant look it up online, and also ask the notary (from a “neutral” business location - not a possible friend of the OP) to explain what notarizing a doc means.If the prospective tenant would not be satisfied by going with a notary after reading 470PC (a felony, or at least a wobbler,) on top of the very acceptance of money for the property under false pretenses being a violation of 470PC (but criminals get away without being positively identified all the time) in itself, I’d, then, say that nothing would satisfy the tenant.I imagine that just mentioning the notary - without having anyone read the legal statute - should be enough.

He would be secured by a second position.