Apple Intelligence 支援繁體粵語嗎？

No, Apple Intelligence supports Chinese (Simplified) and Chinese (Traditional), but not Cantonese. 

See this --> How to get Apple Intelligence - Apple Support

I don't know. The current iOS version is iOS 26.4, which you should be updated to. It's highly likely Apple Intelligence won't support Chinese at all until you do. And then there's the fact that if you're in China, to my knowledge at least, Apple Intelligence is still not supported in Mainland China.