Basically everything about the house elves and the culturally norms around them is extremely problematic. No debate there.

But A) giving an Asian girl an anglicized Asian-ish name is not in itself racist. Chang is a common Chinese surname. Cho seems to be a fabrication and only vaguely Chinese sounding. She definitely could have picked a real name, but calling that racist seems like a stretch.

B) You're calling Hermione "the black girl", affirming a hard finality to her race that very notably was stated by Rowling to be open to interpretation. And of the many films, games, artwork, etc. depicting her, she's depicted as white in the vast majority of cases. It is fine if you interpret the character as black, casting a black actress, etc., but it is silly to treat that as an objective filter when convenient just for criticisms sake.