Are all colors 90% cotton or only the grey color? product info: "other heathers" are 60 % cotton, 40% poly. is that a typing error for "colors" 60/40?

You have to be careful. Some are all cotton, some are blends.

Is athletic navy 100% cotton?

The package says solid colors are 100% cotton, heather is 75% cotton and 25% polyester.

do things fall out of the pockets easily?

No they do not. I wear them to the gym and have not had any problems with losing my keys or anything out of the pocket. I use the back pocket for my wallet when leaving the gum and no problems there.

Which color is 100% cotton? The description suggests not all of them is 100% cotton but it's vague!

I ordered the navy and black and they are both cotton. They wash like a dream and wear great. Am very impressed with these pants and would definitely purchase again.