I have gotten some estimates and that looks like about $30k total if I just use local contractors, If I do some of the work myself and do it as cheap as possible, I might be able to do it for $20k. 

Times change, markets change, interest rates change, but we still hear about these same old "rules" decades after they lost their relevance.The same logic applies for napkin math rules that say that capex, vacancy, repairs, or whatever, should each be estimated at X% of monthly rent. 

I estimate the house could rent for $2.8K–$3K, while the warehouse might rent for (one unit) $2K–$4K, depending on how much work it needs to suit different tenants.

You can use this tool to estimate future property taxes: https://treas-secure.state.mi.us/ptestimator/ptestimator.asp

You estimate vacancy at 8% which is conservative.

I use a different site to get rental estimates. https://propertyprofitcalc.com/RentEstimator

Here are the numbers:Property 1:Purchase Price - 130k Current Zillow Estimate - 166kLoan Remaining - 100KCurrent Interest Rate - 5%If Refi - 6.38%Obviously at higher interest rate my EMI is gonna increase , but at same time I am adding an additional asset which would cashflow as well.

I am not going to say there is a best lending model, but brokers legally can not be paid as much as IMB's, and I tend to be cheaper in more situation than not when comparing a loan estimate from an actual lender. 

So, this is why your lawyer may have estimated high.

I am having a sewer line repair company come out and give estimate to repair vs replace.