You need to ask someone who owns an Excursion 2. You need a hard attachment point at the bottom center of the bcd backpack, like a 1" slot. The front will attach marginally to the strap in front of the cumberbund. Not the ideal setup. Obviously, a backplate, harness & wings or sidemount bcd is better for scootering (clipped in). The real question is what are you using the crotch strap for?
Ryan N to keep my BCD from riding up on me when in the water.