I was actually calling on expired listing.

Go to REIA's and MeetUps in your area and network, listen and learn from people that are actually doing the job in your local market. 

That's the kicker - you can't just assume this stuff for an actual valuation.

He withdraws his $100k cash from the bank account and walks away. 

You can "hide the address",yet they still put the actual address in the URL and on the browser tab. 

And the state law already provides that in both Upset and Judicial Tax Sales, the Realty Transfer Tax is based on the assessed value, no matter how low the actual purchase price might be.In one case I personally witnessed, an old abandoned factory building was sold at Judicial Tax Sale. 

Make sure they actually go to the property by asking them to provide time-stamped photos.

Do you work for this developer, as you have indicated on other forums, or are you actually an investor?

It's totally up to you but I think very few investors would suggest less than 7% on anything with 20 units or less.As for repairs, the 10% you have total is for reserves (I think these are actually pretty good numbers depending on the age of the place).

I have actually learned my current practice from Homeline Attorney Landlord training, here in Minneapolis.