Look at the apps on other iOS devices. Are they all the same? No.
What are you talking about? All the video apps I have used on iOS, the play button plays the video, the pause button pauses it.
Also, as far as I know, people do not use IR remotes with their iOS devices, other than airplay of course. Although I might be wrong about that.
When using airplay on iOS to play a video to your ATV, the IR buttons are standard. Just not tvOS.