if we are a family of 4 and we travelling from tsim sha tsui to tung chung station in HK, which card should be?

If you only wanna travel this trip, you can buy regular MTR ticket to travel, one for each!

And may I know how long you will stay in HK? If you will only stay one day and use many mtr travels, I suggest you get a Tourist Day Pass. If you will stay for several days, you can get a standard Octopus Card, one for each!