Well, if you complain about what she wears, based on your feeling about your son's uniform, you are victimising her. If you complain about her attire based on feeling annoyed about a double standard in dress codes, then you are victimising her. If you complain about her attire to your friends, because you feel you can't complain about other things that are as the result of your friends' policies and you donat want to criticise your friends but you feel fine criticising her then you are victimising her. If you complain about her attire based on being jealous of her body you are victimising her.
You posted first with quite an emotional outburst that mentioned various things, most of which were understandable things to be annoyed about, but not grounds for complaint about someone else at their work place. Why mention all those things if it was really ONLY about the standard of attire?
You have rationalised most of those away (it was a joke etc) but still you are thinking about complaining about this person. But really, honestly, are all those other things just incidental and all you are upset/offended about is the clothing?
If honestly that is the case, then you are on firm ground. If not, then you are scapegoating and victimising someone else unfairly.
If you are that upset about the clothing, and only the clothing, and only because it is inappropriate, then do something about it.
A gentle word to her directly in the first instance would be the best course (not gossiping with her with the other mums, although it would be fine to check with trusted others in a "is this just me?' way).
But straight to a complaint where you have a prior relationship with her superiors does smack a bit of bully tactics in itself.
And tbh, given other things you have said- from the use of the word "stripper" to mention of jealousy, to all the rationalisation, does make em think that if you think that this is just about the clothing for you, then you are in denial.