If you have poor sight lines and dirt has to be leveled and brought in along with a retaining wall then cost per acre could be 300k to 400k an acre or more.

I would need to hire a local management company (or, at least, a local on retainer to be available to deal with issues).

They still retain first lean position even after the transfer of title and your title company will make you sign something recognizing the existing lien.Hope this is the info you were looking for.

Muscle through and pay cash for repairs, rehab, and down payment?

Not to sounds offensive, but everyone's time is valuable.If you are a buyer, you typically don't pay anything to the agent, unless they charge any retainer fee.

What are some ways to structure an agreement where I can retain and rent the property but he can get a good return as well?

Also there should be a lease otherwise it’s a verbal month to month leaseOnce you send the notice if you do not get a response and they do not vacate by the notice end date you can file for a unlawful retainer and start eviction. 

I listened to it on a trip once while driving but clearly didn't retain anything to memory.  

We would like to retain our earnest money deposit.

Does the seller retain the full legal responsibility of the warranty?