Just saw this. But all 4 of them are polarizing and memorable. And they're safe bets to accept another chance on the show unlike others (Dan, Keesha, BB8 Jen Johnson, BB11 Natalie Martinez, etc) who seem to be strongly against ever coming back. But their options might be limited since they might not want 2 returning houseguests from the same season.
Matt's another one who they might ask. I forgot about him.
They won't be playing. It's just 'media day' where different reporters and other people (like Brendon and Rachel) come in the house and play a practice round of BB to take promotional pictures and make sure everything is set. (Someone correct me if this isn't actually the case).
If anything, it means 100% for sure that Rachel and Brendon will NOT be on this season because they were there for Media Day.