If by "pink" you mean faded (where if you wear them beyond merely faded, they do become kind of brownish-gray), then I think that is a hazard of the heather gray color, not the brand, since I've experienced this with several brands.
As far as combo pants, I'd wear them as a less baggy leg plate pant, but they are still a bit too baggy for me to use on the bases. In tournaments where I will be switching off between base and plate, I will change between games unless there is absolutely no time. On the bases, I wear a different shirt, pants, shoes, and hat. And since I have to take my shoes off and take the belt out anyway (to take off / put on the ball bags - I use 2), swapping pants is not that much more time.
GD doesn't make anything, so I really don't know who makes the pants that carry his brand. Just be sure you have the right shade of gray if you're buying from a baseball-is-the-only-game-that-matters vendor, like GD. The darker gray is baseball only
AFAIK.
Fech and CK are roughly equivalent in quality. Between the two, I prefer CK due to a double clasp and a more effective "gripper" waste band for keeping your shirt tucked in. If you are planning on ASA Nationals, you'll need the Fech western pocket style pants (which I hate since the pocket is only useful for hooking your thumbs in while in a Texas boot dance line).