The end result of a localization isn't to 100% preserve every single nuance and detail, but to bring over all the important stuff and as many minor details as possible while still, well, localizing it. Doing things like changing jokes to still be pop references, but pop references that make sense in English.
This isn't a case of "changing someone's name," because they're still Kokoro Hata, Miko Toyosatomimi, and Akyuu Hieda, the important parts (the first and last name) are still all there. This is removing something that's already a minor detail in the source detail. As for why something like "von" tends to be kept - it's a question of it still being in use (and thus, being an actually relevant part of the name, unlike no which hasn't been used in ages), and perhaps more importantly, having been included in the western canon enough times that most people who've read at least a few books or watched a few shows with german influences get what the heck's up with a name with "von" in it. That's the most important distinction here - von has context in western literature. No (at least, as a part of a name) does not, and thus is axed because it has no sense and no meaning as it has not been used in ages and was never used in the western canon, and thus has no context.
And TL's notes are a last resort, not a first, for things that simply cannot be conveyed otherwise. If every small detail that couldn't carry over 1:1 perfectly got a TL note, the margins would be utterly unreadable, or there'd be a enormous reference section at the back of the book that nobody wants to bother with. This isn't like, a history book or something - it's meant for entertainment, and that's why we're going to have these small liberties taken with the source material. You can feel it's stupid all you want, and that's totally fine! But come into this localization with tempered expectations, because it's again, a localization. It's going to include small changes like this where no real meaning is lost, because it's something that's utterly meaningless in english due to a lack of context. There's plenty of stuff that'll remind you this is Touhou and japanese (example: Kogasa. All of Kogasa.), so I wouldn't worry unless they start changing things like rice balls to jelly doughnuts.
That brings me back to the reason why Thailand's localization is different from, say, NISA's localization - because it's a different country, which has had far more exposure to Japanese media. You cannot expect a localization for Thailand to have the same translation as one for America and Canada (and any other english speaking country that can get a copy of this), because they have context due to cultural osmosis that the west does not.
Also Miko's name is based on an alias, which is why it's something dumb and absurd. Frankly I wouldn't be surprised if it comes out Miko herself had chosen that name before awakening in Gensokyo for the sake of having as bombastic an entrance as possible.
