At least two of them, if this report at Craveonline is accurate. Which characters are coming off the bench, how and why? Of course, the first two anyone who's been following the DC universe closely for the past couple of years has to think of is Cassandra Cain and Stephanie Brown. I wasn't particularly interested in The Movement, but now I'm intrigued.
We have to watch out for our expectations, however. These might be just unofficial cameos, not full-blown appearances by Cass and Steph. Or whatever two benched characters they're talking about. While I don't see any reason for Steph not to exist in the current continuity, Cass's mom, Lady Shiva, has been de-aged to her early twenties. This makes Cass as we've known her very unlikely. What we're probably looking at is another Li'l Gotham scenario.
On the other hand, it's Gail Simone, and as far as I'm concerned, DC owes her big time for her relentless cheerleading of the new status quo. Oh yeah, and for the crappy way they fired her not too long ago. She really came through in a big way for them during that uninfinite crisis. So if she asked to use Steph and Cass, the top brass there should instantly say, "Of course. Whatever you say! And once again, sorry for the recent unpleasantness."