Is it possible to make chicken pieces (such as leg quarters) come out with the same tenderness and color as a whole roasted chicken?

Chicken pieces can be made in several different ways and still be juicy-be it oven roasted or deep fried.

Yeah sure. Sear and braise it in a pan. Sear the skin 4-5 mins each side in oil or butter until it's deeply golden brown, then add liquid and let it cook through. OR you can do it as a chicken stew kind of thing (chicken cacciatore is great in one skillet).

Simply cook them as you would a chicken.

I imagine if you marinade/baste them the same and cook them as you would a whole chicken, they'd come out relatively close.