The property wouldn't cash flow unless I choose to pay more than I need to for the (PITI - rental income).

Sad to say but tenants that choose to live in these types of units generally get what they deserve.

I don’t think I’m ruling out anyone in terms of the niche I would choose to target.  

Therefore, I choose not to make the payment because I wasn't sure that it will go through.Anyways, I spoke with the customer service and made the payments now so the account is current again.

It's what I would do in your shoes.Regarding a realtor, I know there are some floating around on this website but if you need, I can absolutely set you up with 2-3 awesome professionals and let you choose which you want to work with!

Fair Housing laws would not fully apply to you, so you can pick and choose how you prefer.

Craiglist, Trulia, Zumper, HotPads...etc) to ensure the largest pool of tenants you can find to choose from.

Construction is always needed somewhere, giving us the ability to choose to not work with clients we feel would be a bad fit.  

And if a seller chooses to dance with the devil by selling to a buyer using that type of financing, then the seller agrees to play by the devil's rules.  

So, safest thing to do is probably send them written notice at their 60 to 30-day mark (sooner the better) that advises them, pursuant to the mutually agreed and signed contracts, since they failed to exercise their option to purchase they may now choose to transition into a month-to-month lease or move-out at the natural expiration of their lease term on whatever date.