Any home here over 10 years old is at great risk of the AC system going out.

I know some property management companies offer this service for a fee, but i can run the risk of them overestimating the repair cost for their benefit.2. is it possible to finance the repair costs from either the equity of the house, or through some other source that would consider the arv?

Investors are the easiest to deal with, but they are also the highest risk since if the spread is not there then they don't buy.

Next to know risk at all.

My risk was the $10k spread between what I had into it and the buyer’s down payment.

It's an easy, no risk type deal.

There shouldn't be any risk of not being able to move in on the move-in date after the lease agreement is signed, should there?

Your right it is almost the same but birdogging allows someone to make money with virtually no risk since you are not doing any contracts.

Bulk REO contains inherent (and sizeable) risk.

Instead of holding on to your loan and facing the risk of interest rate change (since bank receives fixed payment from you for 30 yrs in exchange for lump sum) - they will sell this (to someone who wants to submit a lump sum in now exchange for receiving fixed future payments for 30 years, like an insurance company).The bank is an intermediary between buyers and sellers of assets - they make a cut on the spread and transaction costs.