> would the razor blades be enough?

When I experimented with razor blades I decided they were a liability. Very hard to use without cutting yourself, unless you take the time to fashion a handle. Scalple blades are better.

> sharpening the striker

I like using hacksaw blades, broken to fit the tin. It's nice to think you could cut through metal if you had enough time on your hands.

> LED light and a whistle

Redundancy is arguably more important for the light than the whistle, because it's more likely to go wrong - get a flat battery, get wet, get broken, get zapped by an EMP. I think it's more important, too. If you can't see it's hard to do anything else.

I have no idea about the duct tape or foil.