Recent experience that may help someone in similar situation. Context: my daughter and three friends booked a round-trip to LHR all tickets on one PNR. I had previously gifted my daughter E50K status. When I tried to apply Status Pass (mainly so that all four could hit the lounge) the system gave an error along the lines of "At least one passenger on booking holds Elite status". Quick call to Air Canada resolved the situation and STPA applied manually to all passengers. Only thing I needed was to confirm the names of all passengers on the booking. Process took about 3 minutes start to finish (wait times really do seem to have down for phone calls!)