CX tend to wait until they have a meaningful number of potential interview candidates in a given geographical location before sending out the invites for people outside HK.
As for which questions get asked at which interviews - there is definitely no set pattern here - in my experience, the interviewer will tend to basically make up the questions as they go along (although they probably have a basic idea of the areas they want to probe before you walk in).
They may create a new question based on the answer you gave to a previous question ... no one interview seems to be the same.