Okay, so I booked a one-way fare YYZ-LAX just now, on the advice of people here, so thanks. It's direct, business, so I'll keep looking for a return flight. At the moment they have only ones that fly through Montreal, which would be acceptable, but not ideal, so I'll wait.
As for the Tahiti flights, not trying to do this with a reward flight. I've been told now that Air France is using a plane with flatbed business on the Paris-LAX-PPT route, so I'm thinking of booking Business going out (overnight), and PE or even Economy coming back (during the day.)
Thanks for all the help and encouragement.