Citibank Visa can recharge your Octopus so you should be able to earn points for everything you do!
I can't speak for Citibank, but I thought that HSBC had something in the small print to say that unless you actually signed for the goods and got a receipt, then you wouldn't get the points?
What fees are there for Amex? IIRC HSBC charge an annual fee of $120.