Schools and Chinese Language

I have a question and maybe some people here can help me. We may be moving to HK and our oldest daughter wil be 15 this fall. Grade 8 in the USA. She was adopted from China at age 12 and she is fluent in Mandarin and Cantonese (still is after a few years home) and can read and write Chinese. My question is would she be ok in the public school system in HK (which she would like to do if we go) or should we look at an International School? How do they stack up against each other? If she went the public school route, would she have as good of a chance for University admissions compared to an International school? (She is an honor role student at present)

Also we have a 5 year old who actually has learned some Chinese from her sister. IS it advisable to put a non native speaker in public schools to help them learn in Chinese? any advice from somebody who has done this with a younger child would be appreciated.
Thanks