Any ideas on what I could turn it into to help generate some extra profit?

That would be a helpful addition to your plan as you would further reduce your cost of living.Also don’t forget from that $600 you are planning on getting in cash flow you have taxes, insurance, maintenance, capex, and vacancy to consider.With two homes, you may want to keep that extra $20k as an emergency fund rather than spending it on a third property and then be left with no emergency funds.

Since house flipping has become so popular over the past few years, it's never been more critical to give your projects that extra *POP* that homebuyers will notice as they're swiping through Zillow. 

Our current mortgage terms include a late fee after 5 days, so they’re already paying extra each month and have to split the total monthly payment up between 2-3 payments when they get their pay check.

Private notes require more work than Stocks / Bonds, is the added return worth the extra work?

You are a high w2 earner, The house is worth 110k today, you are buying from your grandma for 60k in exchange for free rent for life, upside ARV of 200k.The costs of owning the house will help provide tax relief on your high w2 earnings, you are buying a great chunk of equity that will pay off in the future, and you and your grandma are doing each other solids. 

If a wholesaler can still profit while provided “full disclosure” and adhering to the rules and regulations of real estate licensees then they’ve earned their profit.   

The reality is the opposite - if it's not in writing then the PMC doesn't have to provide the service or can charge extra for it!

I used all the rent and any extra money towards paying them down.

It may sound nice to pay a 6% management fee but the extra fees can add up to be more than the other company that charges 10% with no additional fees.