That's a good saving eric, though of-course the OP will possibly be flying Y. Overnight? The flights I checked indicated a 3hr layover only...maybe it's just the days you booked. FJ would also be my first choice.
Now here's a thought. If the OP is spending what, a year or more on teacher exchange in Canada, it should be relatively easy to visit the sthn US states at any time, just a short flight really. Have you been to Fiji before carnival? Get away from the resorts and you can have a great vacation in Fiji and arrive relaxed in Canada. Maybe do a short 2-3 day city visit at point of entry to US.
As
aamslfc says it might help if you let us know departure city? You can also customise your profile with your location if you wish.
BTW, welcome to AFF
carnival.