A few thoughts:
Some stuff you should be able to do with the knife:
- cut green branches up to ~2" diameter
- light woodwork - fuzz sticks, fireboard, trap parts, whittle camp gizmos
- food prep, skinning
- split dry wood via batoning (less important if paired with a hatchet/larger blade)
- scraping a sparker
1. "Do-all" knife should be 4" blade, moderately thick stock (1/4"?) Thick enough that you could baton-split things if necessary, but not so thick as to sacrifice cutting ability. A knife that was going to be paired with a hatchet or large chopper could be smaller - 3" blade, 1/8" stock to optimize fine cutting.
2. There should be an index finger groove integrated into the handle, not on the blade. Any handle material between the index and middle finger should be smooth - no sharp point. The edge should come nearly to the handle.
3. Handle should offer some leverage for twisting (helps in splitting). This would favor a fairly wide handle.
4. Blade shape should allow for drilling - probably an elongated spear point.
5. Balance should be near neutral - somewhere in the vicinity of the index finger.
6. Convex edge for a larger blade, scandi for a more speciallized slicing/cutting knife.
7. Materials - people can order what they like, but I'd favor carbon steel (possibly smooth coating), micarta handle, kydex sheath. Easy sharpening would be good.
8. Gadgets - sheath could integrate a loop for a firesteel and some sort of sharpener - diamond plate, small stone, ceramic rod, or mini-steel.