I think fetish is the wrong term here, at the most these characters are adopting something a person could in theory have a fetish about. What's more I do not consider personality stereotypes to be "fetishes" but just that stereotypes, and those stereotypes tend to be grounded in a degree of reality. You do see a lot of the same personality types and behaviors recurring throughout humanity, and indeed there are entire sciences devoted to studying this and finding ways to control or exploit it. Some people find various types of personalities fun or appealing, and indeed some of the more positive ones are popular with a lot of people (obviously) but that's just human nature, and not really the result of a fetish.
When it comes to Anime it should be noted that it has it's own stereotypes and tropes, which while obvious now, was something people argued against back when Anime was starting to become more popular and mainstream, simply because it was new and reasonable fresh in the US at the time. Anime DOES re-use a lot of the same basic personalities for a lot
of characters that fill certain roles, especially when they get the job done.
That said there HAS been Anime where characters have literally been based around fetishes, "Speed Grapher" got into this for example, where say someone's rubber fetish became the basis for their powers. The characters mentioned above might fit certain stereotypes, but I can't say any of them are inherently fetishistic. Even the "gothic Lolita" thing as that is an actual fashion style that can be done a lot of ways, and is practiced by people with a lot of different personalities (and even seen along a lot of characters). Sure, some people REALLY like the look, but that can be said of a lot of different fashions and alternative styles, it's no more of a fetish than Punk, Goth, or whatever, although you might find it unusually appealing when done well by a person you find attractive or otherwise like.
That's my thoughts at any rate.