So, I setup my iPad from scratch and one thing I noticed on the home screen that most of the apps had to be downloaded. Once they downloaded I made a note of the consumed space. Then I deleted several and noticed that my available space increased. This is definitely a change from iOS10. Also, it appears that the stock apps cant be reinstalled when offline - this was possible on iOS10, so this confirms that when stock apps are removed they are actually removed instead the icon being removed. Interesting change for sure.