Kwannon died in Betsy's body. Betsy died in Kwannon's in Xtreme X-Men. She was dead a few years, and was brought back to life or whatever by her brother, so blame him for not putting her back in her original body.
As for 'yellowface' that has nothing to do with her, that is a criticism of Marvel, or whichever creators you want to point the finger at, for pretending they had a popular asian character. Whatever issue you have with that has nothing to do with Betsy as a character, her decisions in the matter, or how her teammates are going to behave towards her.