Hmm... I could see oozes as fungi. It fits them better. As for vermin, the typical insectoid roles are taken care of by plant alternatives. I could see plant-people as thinking they were fungi, though. That would make more sense, with the spongy, pale skins and all.
I think I'll just have to house-rule that precision damage still applies, in all its forms.
On the issue of fungi, I have this image of nocturnal fungus predators forcing the plants back into their cities each night. Is there a fungal template anywhere?