NEW WRINKLE
Just talking to concierge at YYC about this PM's flight to PHX.
Her contention (I didn't argue) was that if the upgrade doesn't clear by flight day and we go to airport control:
"since my wife is a guest on my SE eupgrade credits, even though she is Elite, she comes out below Elites using their own eupgrades."
I didn't bother changing anything to my wife's credits at this late stage but if this is true, it is truly bizarre. Even she admitted it was a bit strange.
Either way, she will fly up front!