Confession: I was a PG slob in 6th grade, and now I'm a PG slob in my mid-forties who relies on 6th graders to help keep my classroom organized. But I do take daily showers and brush my teeth now, and have for many years. My kitchen, on the other hand...
There are a couple of components to this problem. On a crime show, I'd say we have to look at both means and motive. Let's look at motivation first.
At this age, what peers think is becoming much more important to kids than what their parents say, and that's what keeps most kids clean and groomed--sometimes obsessively--at this age. It could be that she doesn't understand her peers, and they don't understand her.
As a PG kid, she may be so alien to her same-age peers, that they may treat her as a freak whether she's clean or dirty, frankly. Peer feedback does not work the same way for her that it does for a kid closer to the center of the bell curve. That's an issue that will either resolve itself in the next year or two, or will get much worse.
A gentle suggestion from adult she knows and trusts--who is not part of her nuclear family--may have more impact than every thing that you say.
These tasks you mention are, frankly, boring. There is no intrinsic motivation, and you probably have a daughter who is all about challenging herself to solve difficult problems and not big into external validation.
I suggest a point system, in which consistent attention to specific tasks (brushing teeth, daily shower, putting dirty clothes in the hamper), earns points, which build up over time to be cashed in on a significant reward (maybe an experience of some kind, instead of an object) which means something to her. For it to be most effective, you would want her to participate--by negotiation--in the creation of the point system. The design of a system that will lead to something she really wants is the kind of task that will appeal to her, and make her feel that the whole system belongs to her.
As far as the means, we are talking about a mysterious phenomenon called "executive function". I struggle with both the theory and the practice, so I'm kind of hoping someone else will step in here.
