Canada's North Coast Trail is one of those hikes that needs careful consideration. You are lucky if you get great weather, and kick yourself for bringing the extra warm clothes and rain gear. You are kicking yourself if you forgot that stuff and weather behaves as normal. Either way, this is a trail best done as light as possible. It is rugged. Over roots, through mud puddles, over craggy headlands-you want to be maneuverable, and lightness is the best way to help that.
This is a great site for researching the best light stuff around. Take advantage of it. If you are going on your own, dig in. If you want a guided trip, there are two companies that run trips there: Coastal Bliss Adventures and Sea to Sky Expeditions. They can save you time and hassle by helping you prepare and making sure you make it all the way through in the best way.
No matter how you go, please prepare well and be safe.