Hi Jason,My understanding of this situation is that the owner wants to sell you a stream of pre-determined payments.

You definitely will want to have your rental criteria predetermined and ask targeted questions to potential tenants before showing them your property.

I would offer them packages.  1) a predetermined (you pick) place to stay funded by you, plus a grocery store gift card to replace food and supplies needed for them to clean.  2) they can stay wherever and you will discount their rent based on a prorated rate and a grocery store gift card to replace food and supplies needed for them to clean. 

As a cashiers check needs to be a predetermined amount, how do you go about doing this if you don't know what the final purchase price will be?  

You would then separately enter into an option agreement which, in exchange for a consideration (option fee) provides them with the right, but not the obligation, to purchase the property at a predetermined price (strike price) at a set time (option/exercise date) in the future.You should keep these two agreements separate with no performance ties between them.  

Our first night, we can discuss future logistics including predetermined days/dates/times etc...

Water heaters (etc.) do not start leaking on any pre-determined schedule.

The other is a hybrid model, where you intentionally look to hold properties for a predetermined period of time (say 5 - 7 years) with the plan to sell the property.Second, the benchmark for me is a minimum cash flow, neighborhood & school district quality and overall location. 

Apartment buildings, spec homes, office, retail, you name it...project doesn't work out and meet predetermined hurdles and/or you can't lease up or sell, game over.2.

Don't pre-determine the rent but rather determine the approximate rent based on the actual property you buy.