Some more little tidbits:
The grizzly has two attacks: Normal attack & BearSmite. Normal Attack hits at 12 FPA, and has no modifiers (same as player's normal attack). BearSmite is effectively a barbarians bash skill with 15% ed, that hits at 17 FPA; it adds another 15% ed, and has a 100% chance to knockback when not blocked (normal knockback abilities are often 50% or 25% depending on target). So any attack by a grizzly will have a 50% chance to knockback, as it could be 'either'.
Molten Boulder has a 50% chance to knockback on striking (when not blocked), but will hit multiple, multiple times. Each collision has a 50% chance to knockback, and will always push in the direction the boulder is rolling (chaining knockbacks together).
A knockback ALWAYS puts a target in FHR, even if it dealt not enough damage to normally do so, and even if the target doesn't move due to a wall.