If buy movie only play on Apple devices?

Thinking of splashing out on the Star Wars collection (again! have it on Blu-Ray, DVD, video!), just would be nice to have it digitally as well. However although I am in the Apple eco system, I have iPhones, iPads, Apple TVs, iMac, if I buy it on iTunes can I then only play on Apple devices? e.g. in future if I bought an Android phone, I couldn't then play it on that?

Also on an iPhone to watch it do I need to download it first to my iPhone? is it only the Apple TV where it streams? I don't really want to use up 30Gb on my iPhone just so I can have them all on my iPhone.

This collection contains iTunes extras as well, are these the same as the Blu-Ray extras on the discs? are these iTunes extras exclusive to iTunes, e.g. Google play has the movies to, are the extras on there the same?

tbh its a little extravagant of me to get them (they are really expensive), as I say I have them elsewhere, its the convenience of having them digitally though....?...