My dad being a Conrail cool-aid drinker, he has basically come up with the same consensus. Sometimes the Q is on the front of the loco, others at the rear. As for multiple sizes, yup, even on the same class of locos.
As for the Dash 8s, believe GE used a bigger logo than EMD and Conrail.
One of these days I'd like to get a pair of Conrail units to use as pool power, seen SD50s in the BN coal lines along with SD40-2Rs. Probably do one of each.