Critique - Jello

Alright, the "teacher" works great during the push-off-desk. The gesture on around x110 for "Who did this?" is a bit broad, it's very "Tataaaa, look at that." You can lessen the arc, where it's a very matter of fact A to B (with a little arc though). I would keep that pose with some life to it as he looks back to the kids (the hand to the chest is very even in terms of timing and slow). You can then go to the folded hands as he starts walking
The walk needs some work, it needs more weight and character, right now it's very still (whole body with arms and head are moving as one), loosen up the upper part. The screen right leg around x206 is doing a weird swing, where the knee is pointing screen right and then moves in with an opposite pose at around x214. Lessen the out and in of the knee.
On "I'm gonna loose..." his bending down to the kid is too big, tone that down because you want the full explosion happening with the other kid. Straighten him up as he says that line. He's stiffening up, preparing for the jump, then make the jump a bit faster and have his head always looking at the kid (with a little nose down for the overlap on the land, but not too much). On "mind" you can have him get closer to the kid to accentuate "mind".

The right kid looks okay idea wise, just put polish on it. The left guy shouldn't look at the other kid because it distracts from the teacher, the audience should always be looking at him. The kid can look at the other one at the very beginning with a tiny head rotation towards him, nothing big.
With FK/IK switching you either match it frame by frame or make the switch happen across a few frames.

Cheers
Jean-Denis