I'll be interested to know if they're playing sith, jedi or something completely different. There is also the chance they could be doing the actual fight-work for the characters in the film, but I feel like that would be a waste of their on-screen talents. We've been hearing for ages the film will do it's best to reduce the use of CGI, and we could see Abrams hiring fighters instead of digital artists.
Lucas being known for this type of shit which we saw in Temple of Doom when exploring Indian culture and most notably cuisine. Eating snakes, bugs, eyeballs and monkey brains in a country mostly known for being vegetarian.