Having a distinct voice for Neville kinda ruins the surprise that it’s Neville standing up to the bullies at first and not Harry, as in the text he isn’t identified right away. But I didn’t really see any way out of that. It’s a detail that is unfortunately unavoidably lost in translation.
It’s also a bit odd when different people pronounce proper nouns in different ways. That may be avoidable, but it’s harder to do when contributors are spread around the country/world and you can’t coordinate in real time. It’s probably not a big deal, since people do pronounce names in a variety of ways in real life – as the owner of a very unusual name myself I’m used to several variations on “Eneasz”. I’ve never had the Data/Data problem. But it feels weird in story form, since the Narrator is supposedly the Voice of God and the characters aren’t supposed to diverge from him. Right? /shrug