You will find that this contract and promise is valid only until it is time to pay you. 

When it comes to property like this, is buy and hold strategy with the idea that cash flow is the primary profit driver valid?

Verbal notice is also not valid in most states, even for maintenance requests I would always require they submit the written request for record keeping when I self managed.  

All systems priced have a ten year all parts warranty and a one-year labor warranty.Trane $4,800.00Rheem $4,500.00York  $4,600.00York system with a 10 year labor warranty $5,100.00Armstrong  $4,200.00We currently have a Rheem, I have read that the older Rheems are great but they are no longer made the same to last.

I specifically remember an attorney saying something to the effect that this executive order is most likely not valid because it interferes with a private contract between two people.

I just installed these in one of my properties at $1.89 per sqft, underlayment attached, and a lifetime residential warranty: https://www.homedepot.com/p/Home-Decorators-Collection-Coastal-Oak-7-5-in-L-x-47-6-in-W-Luxury-Vinyl-Plank-Flooring-24-74-sq-ft-case-03918/300253426

Do you provide a written warranty, for all labor?

We do have a home warranty which should help with repair or replacement but you know how those warranties go they try to do everything they can to not actually replace the entire unit and even if it needed replacement there would probably be a dollar limitation.But my question is assuming it completely dies randomly... let’s say it would take two weeks to get a new unit ordered and installed.

@Mathew Paul you make a valid point but, I would prefer to use my contract.

And it actually might be a bit worse than you imagined - because you have a valid exchange with valid identifications the next time your exchange can die is day 181.