I'd swap the hubs rather than fart around with the freehub swap... or just build a new wheel, a CR-18 is pretty cheap and a good rim I've run into incompatible cones and dust seals when swapping freehubs but I can't speak to those specific models. It's not insurmountable but it can be annoying. You might also want to check to see if you'll need to adjust the wheel's dish after you change the spacers and stuff around.

You can drill a hole in a piece of wood and cut that in half to use as a clamp in a vice to hold the bare hub if you want to swap the freehubs.