As above, my first choice in woods tools is the axe, full size felling (1). Second knives. I normally tote a large hatchet (GB small forest) for late spring to early fall and depending on the duration/ deepness/location and lateness/earliness of season, they get bigger.
I recognize this flies in the face of your ligheness philosophy, but it's my choice based on experience and the wisdom of the old ones who plied the north woods where I play.
All that said, my knives are my always carried, primary go to's. My ongoing testing assures my familiarity with my equipment, but more importantly that my equipment works as advertised and for me how/where and as I use it. It's an never ending process. My question is do you ever test your bivy/contingency gear? Have you made a fire, cut shelter poles, battoned with your knife(s)? Do you know for sure that the knives you carry will survive the process? I battoned a 3" dry round with my EDC hollow ground fixed blade, and the edge rolled, ribboned. A large folder, and the pin and the lock's loose. I understand that potentially ruining of an expensive knife can get pricey, but I'd rather know before I REALLY NEED to depend on the knife or anything else I'm staking my or my families life on. Know before you go. Happy journeys.
