Pretty sure all of them are playing. There were no "stars" or anything saying the last two aren't playing.
If you haven't heard of Heartist, you should definitely check them out. They're signed by Roadrunner Records and they're touring with some big names. They're on the Enter Shikari tour right now. A week after that finishes, they're doing Europe with Killswitch. After that, they're on this tour. I expect nothing but big things for this band.