People make mixed sets all the time. That's the beauty of Mizuno - you can order individual clubs - and since they are forged, get them bent to your specs.
Note: MX-200 lofts are 2 degrees stronger than MP-60.
Look at the MP-52 as well for this option - it has a pocket cavity like the MX-200 for extra forgiveness, but lofts, sole, and offset will match closer to the MP-60.