The sooner we dispense with the 'Will Young is a decent option as an opener' idea, the better. I like Will Young as a player, but he is not technically up to opening in Test match cricket. That ball yesterday, on 5th (at least) stump with no sideways movement, was a classic example. We know about the penchant for playing across his front pad to the ball coming in, too.
If Kane is out, open with Conway - you know, the guy who scored 200 on debut playing there. Bat Young at 3. Then when Kane returns, he bats 4 and allows Nicholls to bat in his rightful spot at 5 + start to transition the next opening partner for Latham into that spot (Rachin, no doubt). Otherwise we're going to get into a position where we shoehorn Young into a spot he's not up to, and we risk jeopardizing the career of a guy who could average 40+ at 4 but may get into a technical and mental glut having to open.