Jack only uses "Juggler" and "Riposte" when he's under the influence of "9 Dragon Potion" (at least I think that's what it was called). It's not at all clear he could do them when not under the influence of what is effectively a powerful combat drug. Even so it's clear that Lo Pan didn't expect him to be able to do anything like that. So maybe he's actually pretty at grabbing things out of the air and throwing them back compared to normal people, just not good enough to do it reliably when not on drugs. .
I don't know about that. I would say catching the bottle from a relaxed position and attitude that was flying at his head that started a mere two feet from his head would seem just as hard, if not harder, as catching the knife.
