What I more so want to do is accumulate assets over time and take advantage of debt pay down and equity build up so that I have that money coming in when the assets are paid off. 

It is a long game to accumulate wealth. 

Your money (initial cash) is still in the property and being used as collateral so the bank can sell you their money.You're still going to be restricted in how many times you can do this based on your accumulated "debt to income ratio".

You take on a house that needs literally everything new and underestimate the accumulative cost effect12.

Then you could easily use those profits to buy more real estate at such a faster rate then holding a job or just waiting for funds to accumulate from real estate cash flows.

You pre-paid 4 years, but the interest will continue to accumulated until you make the next payment, I  don't see the benefit.

@Paul SweetmanSounds like you are in a great spot and have accumulated some wealth. 

By focusing on wellness and a positive mindset, I have accumulated enough cash side-hustling, to start investing in real estate.

If you think you will be able to draw on the equity accumulated by paying down the loans - well, that is a possibility, but it requires going through the bank to ask for permission in the form of a loan application.

I'm not getting rich on it, but it pays for itself and kicks off a little extra cash each month that I'm able to stock away for any big maintenance issues that might come up.Moving forward I would like to accumulate additional residential rental property to hold and rent.