Looks good. Four suggestions:
-A couple of bandaids in a small zipper bag. I know, you've probably got them, but redundancy is good.
-A couple of neon 3x5 index cards, laminated and with holes punched in them so you can lace them together to form a longer signal if someone is wearing the bandanna or using it as a bandage.
-A mini Sharpie or a Lumocolor, which can write on the laminated index cards.
-Duct tape rerolled on a coffee stirrer or something similar.
Unfortunately, not enough space to spare for socks.