Originally Posted by MSPeconomist

This is exactly what I suspected that the T&C for your challenge (this is what I'm calling the contract) would say. It clearly says that you are only supposed to receive benefits when flying DL operated flights. You will not get lounge access in AMS and I suspect that you won't get the elite baggage allowance either. My guess is that you won't be able to use a lounge in ATL either, but YMMV.

You can always buy entry to a SC (but not the KLM lounges in AMS), but this can be expensive. If you have PP, go to The Club in ATL F.