I kind of went through this recently, but in my case I wanted to replace just one foot. I ordered feet from Etsy and was sent the wrong size. Then I ordered from ebay and learned that even though the shape and base were the right size, the slope was different and the tip of the foot was much smaller, plus it was shorter. After that I gave up!
The feet
Coach used didn't have prongs in the center, which is the only type you can find. The height and slope of Coach feet were different too, but that shouldn't matter much since you don't have to match anything. You'll have to dig holes in the bottom of the bag to attach them. Unless you can lift that piece of suede in the bottom of the bag, the prongs will show on the inside of the bag. In your case, I think you should wait until you get the bag to measure the circles on the bottom, because you'll want to come close to covering them.
I think the antiqued brass is closer to the correct color. Even though it is probably darker than you need, it looks better than the really shiny gold.
How about this type?
http://www.ebay.com/itm/Solid-Brass...hash=item5685aa7912:m:mlcxBpav0iXuGSWJ7Cr0qJg
They screw in, so on the inside you'll just have neat screwheads instead of prongs. I've ordered from this company before. It takes a long time to get your package but they check with you to make sure you've gotten it and are happy.