Jared, you might be surprised what you can do with an FHA loan.

Any tips on avoiding unexpected costs or delays during rehab?

This is a new venture for him so I'm not super surprised at the lack of feedback out there. 

James, no surprise here, but title knows the seller.

Maybe your situation is different and if you don’t feel comfortable in the neighborhood then this may be a moot point anyway.As for FHA, my understanding is that you must intend to live in the house for a year  it sounds like you did intend to, but due to unexpected circumstances- lead exposure and unexpected unsafe neighborhood- you have to move.

This surprise turned this amazing deal into something like a okay deal because the lot was still good.

I would be very surprised if they are just keeping your money.

Having cash reserves gave me the confidence to move quickly on a great deal without losing sleep over unexpected expenses.

When we did it, we did score some great deals, but what we found was that we were visiting so many properties to understand our "strike price" (the maximimum we would pay for the property when taking into account rehab costs, hold times, interest on any debt, closing costs, real estate commissions, a contingency reserve for "unexpecteds", etc) that the math started to not make as much sense.

I am comparing both of them right now and while people seem to prefer Propstream, I am surprised to see how many comps do not come up in the search, while Batchleads and even Zillow give me more results (using the exact same filters).