Just called the admission office of CUHK and HKU medicine.
CUHK says they are not offering advance offer this year, so expect to receive invitation for interview in March to April.
For fast-track applicants for HKU MBBS, the date of interview is scheduled on 16/12/2014 and they will send out invitation around a week before. If you hear nothing after 9-11/12, probably your application will be pooled into the main round.
Good luck!