They also go to extended stay places.  

That construction agreement may not be valid without a license.Forget any construction financing, you can't give the property as collateral.If suppliers extend credit for materials, they will generally want the address and owner to sign or a licensed contractor with a valid construction agreement allowing liens to be created.You can file your option and cloud title, but that cloud doesn't prevent an owner from selling the property subject to that option, the new owner will be obligated to sell it under the option, but if you fail to exercise it as agreed, they will own the place.

Can you leave it with the seller in some way for an extended period or can you transfer it to a buyer?

The back splash will go up all the way to the cabinet and also extend into the window area, paint bottom cabinets white, install new hinges, knobs and handle, remove old excess wiring, remove the ceiling fan and install track lighting, install can lighting over the kitchen sink. add new kitchen sink and pull out faucet.6

Basically, if I'm signing a document that covers the extended terms of the sale, that paper is worthless to everyone but you and me.

Is this document assurance of what tenants are paying and lease duration?  

It excludes about half the popular and has limited exposure time (longer duration the older I get, unfortunately). 

One item though, Builder's Risk policies do not have liability coverage attached, so either have a hard conversation with your contractor to discuss this and see if his policy will extend over, or you need to purchase another policy for liability.  

A colleague of mine rented a beach house with his extended family this past summer - 23 consecutive years in the same house.  

He neglected to notice that while his equity increased due to the market conditions, not due to his genius, he over extended himself.