Congratulations on getting a Stage 1 interview! Here is a hotel that could suit your needs:
Hotel Novotel Hong Kong Citygate: travel, stay or vacation, holiday at HONG KONG
The hotel is quite close to the Airport and CX City, where you will be having your interviews. Needless to say it will save you a lot of time and transportation costs. Not sure if it's the best bargain in terms of price, but in terms of geographical proximity, it is the best... of course unless you are keen on staying in the Airport Regal Hotel which is just right next to the airport terminal building and in the vicinity of jet aircraft taking off and landing.
The website should be able to give you a quote for your 10 days' stay. Good luck!