If you look at ROI it is much higher because I increased the value of the property and prices are already higher.If I take a 2% as an estimated annual appreciation and plan 10 years in advance I get around 13% ROI,  but it is hard to say in advance.

Another fairly easy step is a local engineering firm, they can give you the soft cost as well as the hard cost estimates, at least a ballpark per pad up front.

Please don't tell me that you are a data analyst who doesn't know about data rights? 

Learn how to estimate repair costs.

I am still calling and trying to get them in to give an estimate.

My biggest concern at the moment is estimating the rehab costs. 

I'd sell through Redfin at 1% seller's agent fee because we bought with Redfin last fall, so I estimate 6% closing costs (not including holding costs and just need to touch up paint in some areas, but have new flooring, new roof, and recently upgraded electrical).  

If I keep it after I move out, I'm thinking I can cashflow 300-400 per month (~$1500 estimated rent) .

I am fairly confident I can rent this out on AirBnb for around $120/night on weekends during warm months and $80/night midweek and get a fairly decent income from it - I'd estimate conservatively being able to net $1,500/month on average from May - September and $800/month October through April (would love to find monthly tenants, but acknowledge that won't be at 100% capacity during off months).I put in an offer for $40k, which is what I feel like the house is worth in its condition and location - there are a lot of houses in similar condition but with more square footage (this guy is just 650 sq ft) that have sold in the $20k-60k range in the last year.

Did you estimate low?