I don't have a definitive feature list, and I agree that it would be helpful for Ring to include a nice comparison matrix.
I recently installed several Stick-up cams and Spotlight cams, however, and I can answer a couple of your questions:
The POE stick-up cam does both power and networking through the ethernet cable - no wifi required. However, during installation through the Ring app, the app still tries to do a wifi test after you have the camera up and running, and complains that your wifi signal is horrible. Additionally, when you look at the Network section in Device Health in the Ring app, it doesn't indicate that the camera is on a wired connection. Signal strength is shown as -256dB. It would be nice if they would fix this. Anyway, I have 4 stick-up cams connected through a POE ethernet switch, and they are all running great.
Both the Stick-up and Spotlight cameras have motion detection, but the Stick-up cameras have a much better version of it - you can 'draw' complicated motion zones. The Spotlight cameras only allow you to adjust distance in one of three straightline areas.
I bought the battery version of the Spotlight cameras and then bought solar panels in another order - I didn't order the solar version of the camera.
I can see how this information could be more useful on the product pages, and will certainly pass that along to the team.