The processor datasheet can be a good source of info sometimes, LPC2478.
4mA
Check the datasheet please. Pins are 3.3V and 5V tolerant.
They are read when you call the read method. So the update speed is as fast as you can loop reading … so it completely depends on how much work you are doing. What are you trying to measure? How fast do you need it?
I would think you would make the specifications available for the products you sell on your own site rather than force your customers to sift through the clutter of 3 sites -your own, ghi and NXP’s to find basic information. -Or, as you like to say- “FEZ”
Also, you may consider adding a basic “search” to your website. (not just the forum)