Oh my! Let's not record the sale contract, let's record a Notice of Sale Pending or Notice of Pending Sale, or Notice of Lien, or many different descriptions for a letter simply stating that the property is under contract. That is all you need to give notice that a pending sale/closing is on the way. Recording the sale contract gives the whole world notice as to what you are buying the property for, and the terms under which you are buying. Do you want to do that? I wouldn't.
a contract contingency is not really an out startegy, it's an aspect of the transaction that requires a certain thing to happen or be acceptable in order for there to be a binding contract. You need to proceed in good faith to ensure that contingncies happen. A statement for the contract being subject to an acceptable HVAC inspection, means you have a certain period of time, a reasonable period, to complete an inspection and approve of the condition. If you fail to have it inspected and a week after your inspection period you want out, you can't just say, well, the HVAC isn't any good....you have to make a reasonable effort to see to it that any requirement for a contingency is accomplished and carried out. If that's all you said, it could be that the HVAC needs only to be operable and if it works, you bought ! Be very detailed about your contingencies and requirements.