Which ticket to purchase for HK trip?

Hi! we will be traveling from disneyland to Ocean Park for a roundtrip. We will be with 6 kids and 6 adults. Kids age: eldest 11 years old and youngest 3 years old. Can you please suggest which ticket we should get? We will be staying at Disneyland Hotel and we are just traveling once forth and back from disneyland to ocean park. Should we get the tourist passes to save rather that paying per trip on the MTR?