Hi! We,2 adults & 2 kids are going to visit HK for the first time in middle of Sept for 4 D &3 N staying at Express By Holiday Inn at Causewaybay. Please adv which type of card should we buy during our stay? Should we by Octopus or The airport express travel pass ? It is refundable & children half price for the airport travel pass ? our ininerary as follow: D1-from HKIA to hotel then to ladise market, avenue of star. D2-Disneyland. D3-Ocean park, Peak & temple street. D4-leaving HK at 2.45pm, if possible go to big buddha.Pls adv. Thanks