There is a company in my area that it looks like it will cost me about $400 a year per property but after this week I would welcome that "insurance" as I just had a large unexpected AC bill.  

We back into the "strike price", meaning the maximum price we're willing to pay for a property, by starting with a conservative ARV and then backing off our required profit, the rehab cost, the time value of money (carrying costs and interest), and a contingency reserve for unexpected expenses.

My bookkeeping firm provides me with a steady active income, which allows me to keep doing deals, cover unexpected expenses, and navigate the occasional black swan event.My Take on Cash Flow:Cash Flow is a hedge against corrections.

Sometimes, it’s just a misunderstanding—maybe they thought the amount was prorated, or they ran into an unexpected issue.

For flipping, focus on accurate ARV estimates and budgeting for unexpected costs, while for BRRRR, building strong relationships with local lenders that can help streamline your hard money into your refinancing.

Scratch & dent furniture & appliance outlets are your friends!

This is not myface or spacebook or any of those awful social media outlets where people are a**holes to each other.   

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.

Any tips on avoiding unexpected costs or delays during rehab?

It's understandable that unexpected things arise sometimes, especially when you're opening up walls or dealing with older electric or plumbing.