It looks like if you choose an outbound/inbound with a codeshare segment (e.g. AC) it books in P class, if all LH it books (sometimes at least) in Z. P gets 100% miles on Aeroplan but is excluded from the COS bonus. Z gets 150%. (But the P segment on AC should still get you 150%). I don't think there is a 0% earning LH business fare.
Aeroplan website:
"Earn 50% bonus miles for flying in First or Business Class (Excluding Booking Class P)"
https://www4.aeroplan.com/earn_miles...fthansaAirways