Also, all the actors don't have to be together to video their parts... unless they need to wrestle with each other for some reason. It's all blue screens.
You don't see that with Breakout, because Disney made their eye gazes match, and so, they *appear* to be together.
You want to see what happens when you film separate scenes and it is obvious the people are not in the same room with one another? Take a ride on Gringott's. Hey Bellatrix, what are you looking at? It's certainly not Voldemort you're looking at when you look over your shoulder.
Of course, same issue when characters have to interact with CGI characters, the ones doing post production have to make sure everything aligns, isn't that right Dr. Nigel Channing?