I just did a weight comparison, Linen Micarta vs. G10. The G10 weighs about 30% more than Micarta. Durability with any of the Micarta products should be well suited for backpacking. Hickory, Osage and Red Cedar are lightweight, strong, readily available and low cost. I have made some Hickory kitchen knives and sealed them with Tru-Oil and they are standing up very well. My favorite camp knife has an Osage handle. It has taken some abuse but keeps on tickin'.
If I were making a backpacking knife, I would design the handle to be fairly deep, skeletonized and with a tapered tang to reduce weight. The increase in depth would allow the handle material to be thinner yet it would still be comfortable. If done properly, the trade off is considerably less handle material for a tiny bit more metal. Hope this helps.