The inflator hose is a popular place to mount it. Just make sure it is someplace where you can easily reach it. If you only have the one knife, I would recommend it being in a place where you can reach it with either hand. I don't think I would put it on an LP hose, but that's just my opinion.
As for having a pointy knife around the BC, that's personal preferance really. I generally don't go flailing around with my knife, so I don't see it as a problem, but I've also never really needed the pointy part of the knife either, so I guess not having it wouldn't be an issue either.