Interestingly, despite significantly fewer upsets in the Thief division than anywhere else, the mean skill remaining is still second-lowest (with all divisions within a range of under 1.3).
On the other hand, the average seeds remaining are:
Witch 74.8
Chapel 71.4
Gardens 69.2
Thief 65.9
So the upset meter does indeed swing heavy toward Witch and away from Thief.
LowPants is the lowest mean skill to advance to Round 3 at just over 30, although mrdudesir is still alive in Round 2 with a mean skill of 26.2.