Qld strata law is definitely NOT my area of expertise but you will find more about the workings of a committee HERE.
It does sound like this person is a bully and a potential pain – with that in view, don’t hesitate to assert YOUR rights, because she certainly doesn’t have any problem pushing hers. There is nothing sneaky or underhand about wanting to be on the committee and even if your neighbour gets on, the committee can’t pass by-laws or anything significant like that. Thathas to be done at a general meeting.
I would get yourself acquainted as soon as possible with Body Corporate processes (and you can start by going HERE) and I certainly wouldn’t start by having a go at the strata manager. He or she could prove your most powerful ally