I think the big announcement will be Harry suddenly not attending, realizing his child's birthday is more important than the coronation. Then feeding off that news cycle for a bit. He knows he's out, she knows it. Now they get a chance to spin it even further. That or divorce. It's still utter chaos but I don't think even Oprah will touch them with a 10ft pole. Say what you will about her, but O can read a room and she's been dead silent.
ETA: Oprah's relationship with the public, with the Obama's, with news media in general can be impacted by this. She's not sticking her neck out for them