Of course during those time you will have deposits and possible extensions (something for your attorney to work out)6)It is all case by case, best to find out what is needed is to talk to the local city, some want the moon, others just a plat and site plan.7)We always create a LLC to purchase the property, keeps some secrecy but is more for legal reasons.8)very subjective questions, all depends on what you want to see and what your investors want. 

Excellent ideas here, @Lucas Carl  I use a similar strategy for my LTRs in order to reduce the impending stress caused by tenants with the wrong mentality.Reading your post brought to mind a question I've never considered before:  are vacation rentals subject to Fair Housing Laws in the same way that LTRs are?  

Short terms rentals, by comparison, are subject to market demand and cancellation. 

You would want to get the deed in your name with a mortgage lien placed on the property in the seller's name.Or if the seller doesn't own the property free and clear to be able to do seller financing, another possibility would be a subject to sale.

Consult a real estate attorney to advise you how to structure a purchase "subject to" the existing financing.

Does it say funds will be returned when the subject property is sold, or something like that?

USDA and VA loans are both 0% down loans, FHA is 3.5% down and conventional can start at 3%-20% (lots of programs inside those types, like the homestyle loan etc)  Also if this is an investment home, you could negotiate with the seller to finance the note or take it 'subject to' with little to zero down also. 

Not following appropriate exchange steps will make your exchange void and null and you will be subject to pay the capital tax gains on the sale of the property so please reach out to a QI, accountant, and a qualified real estate agent before you proceed to the next steps.

There are few books out there that are well written on the subject.

"Worth it" is highly subjective.