At the last Realms, I qualified in the sealed qualifier with Jaina, Ryno, and Graccus. I then played Marlowes in the constructed qualifier. Then on day 2 I played Haruka, Thangal, and Morova. So yes, you can play with a different team than you qualified with.
"It's like Michael Jordan going to the YMCA to play basketball."
WOW Minis Judge Level 1, Tourament Organizer, Player Management Level 1