A diagram isn't, in my opinion, a good method to show that information. The best way to look at when the different elements are used is to create a project and see for yourself - after reading about it.

As for your second point this refers to other articles. Ones like https://medium.com/@stevenpcurtis.sc/subclassing-uiview-in-swift-d372c67b7f3 goes some way to describe what you want, and there will more more that I create that use these language features.