I agree with most comments above, it is very likely you will have the property in your possession again in a few years, the other issue is, lets say you apply $200/mo of the rent to principal, because the tenant is "renting to own" Fannie Mae, Freddie Mac and FHA do not recognize the additional rent paid to principal for down payment, because they lend on the purchase price, and no matter how you word it, they will not accept $10 or $20K as Down payment for the loan if it was paid to you over time. also if you need to remove them from the property it is possible a judge may see the principal payment as equitable interest in the property, there are many hag ups in this strategy. 

I recommend looking into the local credit unions first (Charlotte Metro, Truliant, etc.).Also, in addition to the meetings @Karen Rittenhouse mentioned, I'd invite you to come out to the next networking meetup of local BiggerPocket members:Charlotte, NC REI Networking Meetup - Tues.

Additionally if an investor has a non-recourse loan with certain carve outs then they might be able to walk away in down turn and (dump the debt) without affecting their own personal finances or additional assets.

Additionally, I travel a lot for work and haven't been able to find a good strategy to generate leads as I'm always away.

In addition, you need to make sure you have the proper paperwork and you set them up correctly.

My vision is to have an additional sources of income.

I'd need to do a master suite addition to be certain of exit values around $500k but the home previously had a swimming pool and it was where the addition would be.

One of our neighbors has a house that is supposed to sleep no more than four adults,  but twice this summer there were 18 to 20 kids in the house and it was booked through Airbnb.

In my thinking, it is what I had for the past two years, a couple with no kids, but perhaps there are other profiles that work well too.

Help them to decide whether to knock property down and rebuild and hold OR just do some additions completely gut and remodel and sell.