Protective mechanism I suppose.

Everyone I know who doesn't have a regular mechanic, and needs one, hears about my trusted mechanic.

Lock in your insurance rates as long as possible then I would even figure out some sort of swap mechanism or short mechanism for companies that will suffer as a result of hurricane losses - you can buy leaps once you identify a company that will suffer in the event of a catastrophe.

I can see that as a "training" mechanisms.

You would then be responsible for Buyers and Sellers costs, including transfer fees, back and prorated taxes, liens, water, sewer, HOA fees, mechanics liens, any other liens (if any apply,  you'll need to check).

Next best would be an investor who has this type of experience in other towns - if you understand the mechanics of how this is done, you can find the right (connected) service providers and take it through the process in any town. 

I was thinking about placing a mechanic's lien on the property and then creating a promissory note for the seller to give me rights to rent the property out to repay me for repairs until my lien is satisfied.

The wild randomness I see in the comps without understanding the mechanisms that cause the randomness make it tough to set a confident ARV when it comes to negotiating the purchase.

Here we use attorneys to close transactions, but the process is the same.As the seller I do not think it makes any sense to hire a realtor in this type of situation as long as you are familiar with the mechanics of a transaction and have a good title company. 

Have a qualified, insured/bonded roofing contractor do the roof repairs, and licensed tradespeople handle the mechanical repairs.