Your requested terms eliminate the possibility for them to do so.Keep renting until you get your self together from a qualification standpoint to purchase.  

The only thing that will prevent you from qualifying for the loan are you typical qualification guidelines - income, debt to income ratio (DTI), cash reserves (6 mos), etc.Again, though, if you are going to buy, fix and rent out a property, that is not flipping.

The qualification among hard money lenders can vary significantly.

I would have these terms included in the sales agreement and time the actions accordingly.You can sell the property on a land contract now and for the 20k you would allow them to take early possession now with a promissory note due (balloon) at the estimated time of credit qualification. if they don't qualify within the estimated time agreed upon you can find someone else to purchase the property and keep all monies that you receive while they have physical possession.The terms of the promissory note would have a monthly payment that equals the monthly mortgage payment made payable to you or the bank for as long as it takes for buyer to qualify for a new loan to payoff the promissory note.

Or they are looking for a lenient landlord who doesn't have renter qualifications, or will relax them.

I hired my staff from upwork, I do have to vet them and triple check their qualifications.

Just because they are retired doesn't mean that they get a reprieve from qualifications.

 ( I say "potentially" because there are other qualification / requirements besides your credit score.)  

Anybody can get a POF or pre-qualification letter.

Or, do I have to hand them an application like I would any other tenant, and once I see they do not meet the qualifications, get rid of them at that point?