I'm attempting to find a accurate value for a 3/2 house that's was original listed for $410k to do a live in flip.

The area has a surprisingly high occupancy rate per AirDNA and that appears to be fairly accurate after confirming directly on AirBnB.

Just my best guess for you and probably nowhere near accurate.

sounds like you were good with the negotiation but not so much on due-dilligence, accurate assessment? 

My main concern is finding accurate/appropriate data that helps me make a informed decision on a market.

How accurate is the $220 for operation cost?

Not sure how accurate that is.I would look to learn as much as possible on BP etc and just start righting questions down and grasp the understanding of the businessAlso don’t believe people when they say this business is all rainbows and unicorns.

As a professional, a contractor should have a reasonable idea on how long a job will take and the cost of materials..... not exact, but a reasonably accurate idea.

We are buying each home for $148,000, with $500 in earnest money, and the Zillow value (which I realize isn't super accurate) is about $165,000.  

For the HELOC - I was told by both a mortgage company, and a local bank, that we'd need to own the property for 1 year before refinancing - but seems that may not be accurate.