Well in the first movie, Simba had help from the lionesses and rafiki. Also, hyenas are terrible at fighting. They aren't even comparable to lionesses. I'd say each lioness could probably take on around 4 or more hyenas. It looked like there were at least 10 lionesses surrounding Simba, so that's much more of a threat than the hyenas. Regardless, when it's 10+ vs. 1, your going to lose even if the 10 individually are much weaker than you, because you just can't defend yourself against 10 enemies at once. It's not possible.
Anyways, I hated all of the scenes where Pumba and Timon were stalking Kiara. They got caught EVERY SINGLE TIME. It would have made much more sense for him to send Zazu, and I like his character more, but sadly, in order for the plot to proceed, it had to be Timon and Pumba.
