Flush the water heater and check that both elements are working. 

Going to use these feedbacks as talking points to flush out the structure with my cousins.

This can be small stuff like door weatherstrip seals, dual flush toilets, etc.

You might be flushing that deal down the tubes because at this point you are coming off as petty and they don't want to be in contract with you for 2 months.

Beyond the legal concerns of that, how do you force someone flush with cash in the pocket, with a history of not paying their bills, to do exactly that?

I can't put an Amazon link on here but I got something from Amazon  that is called "SunCourt Flush Fit Register Air Booster"

We own old houses, if there is a backup and it isn't caused by the tenant doing something like flushing chicken bones (true story) then we will cut them some slack and teach them to avoid it happening again. 

Who flushed them? 

You don't call Bank of NY when your door squeaks or your toilet won't flush, and your buyers won't either. 

on low end rentals which those are based on rents.. 50 to 60% operating costs before mortgage is were these flush out after a 5 year run 90% of the time.