No experience with this trail, but first, I think you should lay down some "known" things for planning, e.g.,
1. Have your friends done this trail before?, If so, what were their experiences?
2. What time of year, or more importantly, what type of weather? What is the worst weather you could reasonably encounter?
3. How remote is it, e.g. cell phone coverage along the trail or not?
4. How long do you expect to be "out" on the trail?
5. What is the worst case? How long before rescue?
6. "Trail" suggests it is a traveled/known route; What are the experiences of others?
7. Are the backpack kids on the trip or not? And how does that change planning?

In short, I suggest that the devil is in the details. Don't try to prep for TEOWAKI, but make some plans for the conditions you might reasonably encounter. If the trail is, say 3 days from a worst case rescue, don't plan to restart civilization.

You are right in asking for advice/assistance: that is the first step!

Also, a quick search revealed a website about this trail that states "All Persons Planning to hike the West Coast Trail must read and understand the material in this guide to prepare for their hike" . . . " It has the reputation of being one of the most grueling treks in North America. It is isolated, strenuous, physically challenging and potentially hazardous" . . ."Hiking the WCT demands stamina and expertise in hiking and backcountry camping skills. Only competent backpackers should attempt the entire route. You are required to cross deep gullies on fallen trees, negotiate very steep slopes and follow an irregular, slippery trail. This is a wilderness area and it may be many hours before help can be obtained should an accident occur. All hikers should carefully evaluate their individual and group abilities before attempting the route." So, it sounds like your question/concerns justify careful planning. Quote from: http://www.westcoasttrailbc.com/trail_guidebook_map.htm