I really like Fish4esl's advice on this.

I think English with Chinese subtitles is the best overall. At least they will hear the English. I think if you show it in Chinese, the subtitles will be ignored.

If you have time, try showing some movies once each way- first in Chinese to let them get the story, then again in English so that they can map the words they hear onto what they know about the movie.

I do think movies can have a place in an English program, but it's easy to overdo them. In most movies, even kids' movies, the language is too fast and too idiomatic to allow much teaching utility. But a bit is good!