Whether working on cars, airplanes or boats, I don't know how many cotter pins I've been able to get off with just a flat bladed screwdriver to push the ends straight enough to get off. So I'd think I'd be able to do that to the tiny pin in your brakes. My Shimano brakes have clips though. But again, a flat bladed screwdriver can be used to push the clip back.

Although I wouldn't carry it, a small pair of pliers should be no issue for a bike bag. But what about the pads? Do you have a spare set and room for them too?