Let me get this off my chest now.....nobody carries a PLB when the "smallest" survival kit will be both carried and used. If you are carrying a PLB then you are equipping yourself with a backpack (or other) and planning on spending time outdoors. "What if you are separated from your backpack...?" well then you are in all likelihood separated from your PLB too.

Ok....smallest survival kit. I personally take Doug's kit and add whirl bags (breast milk) and potable aqua tabs, plus some hurricane matches, squeeze light, and a heat sheet and put them in a aloksack bag. That is paired with my always on me EDC (knife, lighter, flashlight) and will be carried on-body when necessary, or stuffed in a briefcase/backpack, or tossed in a bag while traveling.... This adds some water storage and purification and extra fire starting. I almost always have a firesteel with striker plus small pill container of cotton balls with vasiline on me as one of these always is in any of my go-to jackets.

This plus knowledge should work for most of N. America. Knowledge trumps all.

BTW, Cody Lundin's first line kit is based around a Mora wrapped with other stuff and worn as a neck knife (per his 98.6 degrees book)