What is the total estimate rehab cost?

I've heard https://www.rentometer.com/ a few times on the BP podcasts, although I will say that the estimated rent for my current property is about $200 higher than the range it gave me.

My lender's estimate for title is very high.

(The assessed value is only 35% of the estimated value, and then the tax is only 3.5% of that .)  

I’m estimating having to put in between 40k and 75k for the down payment but would really prefer not to trade for equity in either a new real estate investing company that I would create for this purpose or my current business.

@Bill Brandt They do but the estimate is not very reasonable.

Again just estimates from any with experience having done extensive multifamily rehabs would really be appreciated in order to see if my numbers are within the ballpark of making this work. 

A site such as Zillow can only use an algorithm to come up with a rough estimate.

I went ahead and estimated my taxes based on my assumption, paid more taxes, and filed an extension. 

Also when on the phone with a seller, how do you quickly come up with an estimate for their property- I know you definitely don't want to tell them you'll give them a callback, you want to give them something to think on while you come back with the Maximum Allowable Offer.