I am travelling with 2 senior citizens abv 65 and my 2 yr old son to Hong Kong via air. Can you please advise what kind of transport cards to buy for HK travel? I read that there is MTR day passes but some tell me to buy Octopus card. What is the difference? Which is the cheapest and best card to travel around?

I want to travel to Macau for 1 day also. There are many kinds of ferries, jets etc that I'm confused. Which should I take and how much?

Your help is most appreciated