Buddy Guy's
confirmed for Saturday, so I don't know if Jack White can make it in Naeba by then. I assume he'll headline the Field of Heaven or Orange Court, so maybe.
And I agree that Jack White is a toss-up between Green sub-headliner and White headliner. I'm personally leaning towards White, but yeah, it could go either way.
As to the Saturday headliner, they're raising ticket prices on May 19, so perhaps they won't announce it until then? Although they usually announce the day-to-day split in late April or early May, which is when we normally find out who the headliners are. But they haven't exactly been following precedent this year...