Over the past few years I redeemed SkyMiles on trips which included FB-operated segments on AF and AZ codeshares.

That said I am sure one cannot redeem SkyMiles on EY-operated flights under KL, AF, AZ, and OK codeshares (i.e. AUH-MLE OK3190, KL3916, AF3814, etc).

So, my conclusion is that it's possible to redeem SkyMiles on some SkyTeam airline codeshares operated by a non-SkyTeam airlines, but definitely not on any codeshare.