Hi Priyank,
If you have already communicated with HKUST on your current scenario, they would have taken note of your status. At this stage, I think the only option is to wait and see if you are invited for interview by HKUST.
In the meantime, you can talk to cuhk and ceibs and ask them to defer your payment by a week or so, if you hear anything positive from hkust.
about the reputation of cuhk and ceibs, cuhk is very well known in HK - globally, not a lot, but as an asian business school, its high ranked.
ceibs is a top notch school, but its biggest drawback is the mandatory mandarin requirement. If you are looking for jobs in china, and in shanghai, then you must speak mandarin. Its gaining a lot of momentum and reputation as people focus more on china. China is the giant of the 21st century, and that is where the action will be based, atleast in our lifetime, so this is the country to be in if you want to make your career.
now your career choices appears to be in 2 opposite directions - if you want to be in commodities - take up cuhk as hk is a finance hub but if u want to go into consultancy, then ceibs is the right choice for you.