At the risk of tooting my horn, I'm a YVR agent.

But you didn't mention something that could be rather crucial. Are you trying to 1. do Mardi Gras and if so, 2. get last minute space? If you are, it might be a plan to see if you can afford hotels there during this time; they will be a lot more than the airfare.

Edit: just checked the main site, www.nola.com and it's 11 days away, so am assuming that you want another time as the best fares have an advance purchase period.

The 14 day advance fares ex-Seattle are US$184.19 [CA$227] before taxes. Considering the cost of the bus or parking at Seatac or the extra time to get there, you could also consider using NW from Bellingham with base fare of US$221.40 [CA$273]. Lowest published base fare from Vancouver is $470.