I want to use it as mechanism for information and to help others grow but not actually selling anything. 

That number also include new mechanicals. 

Not sure about the mechanics of how this works when buying rental property.

I am also a mechanic and i learned years ago that is a but for every seat, because I've seen a lot vehicles and say who would drive that thing and someone always does.

The contractor could put in a mechanic's lien. 

Key stipulations to keep in mind would be disclosures (lead based paint, structural/mechanical/public safety, insurance claims history) and which items do and do not transfer with sale.

I got a higher end freeze-proof faucet that has an internal drain mechanism to relieve pressure if a hose is left connected, but I would bet he isnt going to leave a hose connected in the winter again. 

It's not absolute just one mechanism among many with due diligence and a purchase and sale contract to try and keep the seller honest. 

I know about necessary egresses and about quick release mechanisms for window bars and about alarms vs. window bars... 

A great many more forum posts about people looking for guidance on the specific mechanics.