Thanks for the info!

I did finally get a chance to call in, clarify the Companion Fare rules and book a return flight X 2. The call centre rep was very helpful.

I didn't book an open jaw and wasn't able to book multicity, as per Darren's info. The only option was to book a straight return flight, from the list of published fares. I couldn't even create a mini-stopoff by taking an early flight to YYZ as a connection, as it wasn't a published fare. Possible option right now is perhaps using the Gold benefit of changing to an earlier flight at check in for the outbound--that might work subject to availability.

For our purposes, it is +1 for Aeroplan for ease of booking rewards with options and online bookings.