My return grip usually depended on the serve I am expecting. Big first server just looking to block back with continental grip. If I'm looking to attack a return (2nd serve) I usually hold my forehand grip to show my opponent I'm looking to attack.
As far as feet I prefer to have my outside foot infront of my inside foot. I'm right handed so deuce side right foot add side left foot. I do this (especially on duece side) because a T-serve will get to me quicker and I already have my feet mostly set. A wide serve usually has more spin and a longer distance to travel so I have more time to adjust my feet.