The contents of a ditch kit will change depending on where you are and what you wear on your clothes.  I will assume the following: this is for canoe country and the person will be wearing some kind of utility knife.

1) Compass: minimally important, you are probably not going anywhere and a map would be more useful than a compass.  (And if you wear one as many do, then totally no need to put in kit).
2) Blade: not needed, wearing utility knife.
3) Saw: Many utility knives can serve as a saw
4) Fire makers: YES
5) Medical: YES
6) Containers: No.
7) Food/water: no (water all around).
8) Signal: whistle and mirror (if whistle not worn)
9) needle/thread: needle, safety pin, and some kind of thread/string/line that is very small yet strong.
10)Small bit of duck tape
11) Space blanket

Basically, stuff to stay warm, deal with medical problems, and signal for help.