I've searched around and think I've got most of my questions resolved. This will be my first visit to SIN in 25-ish years, so even if I remembered anything, the only useful thing that remains in my memory is the delightful arctic-like weather.

Airport transit to/from - Staying at Sheraton on Scotts Road. Most efficient transport to/from airport? Options? Approximate train / taxi costs?

MRT Fare payment - tap/enter/exit functioning properly with foreign credit cards?

Best apps for getting taxi or similar services? (I also assume that any taxi will accept a CC payment.)

And for two people, how much cash on hand do you think we'll reasonably need for 4 full days (as opposed to paying for things with CCs).

Suggested arrival time to SIN for evening SQ J, allowing for some reasonable lounge and perhaps shopping time?

Any further unsolicited advice also welcome!