...Also when she smells something weird, she will breathe with her mouth open...

I have sometimes noticed mine doing this, he has his mouth just slighty open and seems to breath the air in over his tongue making a slight noise (I have managed to replicate this sound by making quick gentle breaths through my mouth whilst my tongue is touching the roof of my mouth - why did I do this? I don't know I just put it down to "cat owner" behaviour)...anyway, apparently cats have extra "smelling glands" inside their mouth that they sometimes use to further analyse smells they might encounter...