EA and DICE do not have permission to use Episode VII and future Star Wars content in Star Wars Battlefront, which is limited to historical settings–so don't expect to see Kylo Ren face off against Rey any time soon.
If you're expecting to see these characters take on each other, you'll have a while to wait. Star Wars Battlefront is, according to EA's Blake Jorgensen, limited to historical canon.
Speaking at EA's 3rd quarter earnings call, the EA CFO said:
"On Star Wars, the one thing that we are adhering to, and I think this is part of our arrangement with Lucas and Disney, is you can’t make a game in Star Wars that violates the canon of Star Wars. Meaning, you can take something from the future and bring it back into the past unless it’s a reference. Not knowing yet exactly what the storyline in Rogue One is going to be, I can’t comment on how that could come in. But to the extent that it’s in the future around our current Battlefront game is all paced based on the historical Star Wars canon, which is 30 years before the most recent movie. That will limit our ability to bring some new content into that."
He did however add that future titles will not be limited to episodes I to VI, stating that future Star Wars titles from EA will be able to tap into the new characters and vehicles.