William welcome to the blog and good luck trying to make Zillow into anything but a fount of misinformation. I was an appraiser for 20 years until I got fed up with the banks and agents grinding me for $50 off on appraisals. I got my brokers license 10 years ago and just retired it and myself 2 years ago.
Back when I was appraising a couple of companies tried to get machine generated appraisals as the accepted way of getting a value. They even sold several banks on it but all it did was cause problems and was finally dropped. It didn't work then and I don't believe it will work now.
There is no substitute for human inspections and a general feel for the value of a property. You cited a number of problems that I don't believe can be overcome. From my experience I don't think the MLS or agents will give the necessary information to make it work.
Sorry to bumkick a new member but the machine generated appraisals caused me so much trouble I'm still mad about them.
Good luck,
donrock