@Hai LocDollar General almost never exercises lease option renewal.

It states that:[T]he corporate form may be disregarded and individual shareholders held liable for corporate misdeeds when (1) control over the corporation by those to be held liable was so complete that the corporation has no separate mind, will, or existence of its own, (2) control over the corporation by those to be held liable was exercised in such a manner as to commit fraud or an illegal act against the person seeking to disregard the corporate entity, and (3) injury or unjust loss resulted to the plaintiff from such control and wrong.The test is conjunctive and requires that the plaintiff can satisfy all three prongs of the test.

(For simplicity For this exercise let’s just assume 0 for tax, insurance and other expenses).

If I'm not mistaken, a regular option locks the seller into doing business with you (the buyer), whereas a flex option allows the seller to market their house and sell to whoever they like, until you exercise your option to purchase.

Then either exercised the option or sold the property with a double closing. 

Your situation may differ and I would use all your same criteria (on all parties) and exercise extreme caution....if you are building a pool of applicants, the couple with no documented income would not likely be at the top for me (not sure what the the commission only single salary gig would be, but probably not a front runner in my pools or even meeting minimum criteria)....and you still have to even verify the third party payer would be credit worthy and even interested....

My suggestion is you teach yourself how to "read" comps, all the data points e.g. price per square foot, lot size, bedrooms, baths, number of rooms, and how to categorize by distance from the subject property (a 3bd 2 ba home 1/2 mile from the subject in the same zip code might be a far cry from a similar home 1/2 a block away).Go look at comps as an exercise.

You never pay the taxes, you just keep exercising your right of first refusal to buy subsequent year's tax liens, until you are ready to foreclose.

Often that means exercising some discipline and responding after some time has passed or re-reading things before we hit send. 

Getting the right tenant is a numbers/statistics exercise.