I'm not sure how you are defining a partner. Any of your eligible pass riders can fly on ZEDS. YOu may be able to register anyone as a companion (I don't know about AC) and they could fly on a ZED. I believe that this applies to most ZED agreements.

Be aware that it'll cost you about $150.00 each for departure taxes out of Great Britain. You might want to fly out to Ireland and then on to Canada or Europe to Canada. It might end up costing you the same, but you'll get another trip out of it.

I think this info is correct, but if anyone knows better, I'm all ears.