bmi diamond club - Mixed class redemption on one PNR?

I'd like to book a Z1-Z2 RT redemption, outbound in C, return in Y (C not available).

There is a good chance I will end up canceling the itin, so I'd rather book it as a RT under one PNR to have just one cancellation fee.

Can I do this and still pay only for Y miles on the return? (15K miles total).

Can I do this and still pay only for Y miles on the return? (15K miles total).Unless this is a BD flight and you get a free upgrade to C (as a BD Gold), you'd pay the one-way C plus the one-way Y miles in total.