Does the Connect work in the same way as the Connect Pro with the D2? What will be the difference?

You will be able to use either Connect or Connect Pro together with D2 series flashes. And in both cases, you will benefit from 100 channels and absolute power feedback. The difference is that when you use Connect you can only view the absolute numbers for your settings on your lights in the Control iPhone/Android smartphone app or Control desktop app. While with Connect Pro you will see it and control it in the display/directly on the remote or via the Control smartphone iPhone/Android app or the Control desktop app.