Nice work. If you have the time and continuing interest, I'd be curious to see a breakdown for strips 501 through 1000. This is mainly because I get the impression that Hannelore, despite having debuted rather later than Raven, has since overtaken her in appearances by a wide margin. Which, I suspect, is no coincidence, as both women arguably have a similar role in the strip--the "quirky but strong and loveable" character who gets off to a rough start with one or more of the main cast, but soon wins their respect and friendship.
In Raven's case, Faye and Dora (especially Faye) initially have little respect for her because she's ditzy (to put it kindly), boy-crazy like a teenager, and a trend-follower. But after days/weeks of working alongside her, they come to see that she's genuinely kind, sweet, and often has keen insight into people, and so they count her as a friend. Still, one gets the sense that there's only so much even a writer like Jeph can do with a "noble simpleton" character.
Enter Hanners, who gets off to a rocky start with Marten, who sees her as a provider of unsolicited relationship advice, then as "crazy," and even a dangerous stalker. But he, along with Faye and Dora, quickly warm up to her because under all the mishegoss is a good person, and one whose vulnerability and insecurity they can all relate to. And from a storytelling and characterization angle, she's much more complex and versatile a cast member than Raven. She's inconsistent in her OCD (multiple ear piercings and she smokes) but unapologetic about it. She wavers from painfully shy and timid, to confident and brazen, and back again. Hanners also shows more willingness than Raven to expand her horizons, for example taking up drums and jamming with Deathmøle. So that's my theory as to why Hanners has--if my hunch is correct--usurped Raven's role in QC. But I wouldn't mind seeing the frequency stats, because it might just be that Hanners makes a stronger impression on me than Raven has in the latter 500-odd strips. (I still like seeing Raven, don't get me wrong, but if there were QC Oscars, Hanners would get my vote for Best Supporting Actor.)