If the agent found the deal, he needs to work out an agreement with either you or the  buyer.  

That's all a prenup is - What's going to happen IF this doesn't work out. 

If he has any ethics, he will either pay the bill or call the sub to work out whatever disagreement they have. 

I wouldnt be too happy about a 6.5% CoC with the regular lease, but since it sounds like you could make significantly more renting it by the room, It is definitely worth the risk since you can always just rent it out on a single lease if renting by the room doesnt work out. 

If things don't work out you still have something in your back pocket.

It offers amenities like a work out facility, internet, a pool and front yard care in the HOA.

I would say yes, if all the #'s work out and your living in the other half and your only paying a little each month. 

Can you work out a situation where you  give seller a down payment and  work out a date in the future  to close and then  rent for the  interim ?

The numbers will likely work out (glamping has incredible returns), but you gotta love outdoor hospitality.

I am trying to work out the process of getting the approval amount right now.