Resource gathering tools

Are the pickaxe and woodchopping axe that yarbok sells the only way to harvest things like trees and ore? Are there other pickaxes in game for example?

You can harvest trees with any weapon that does chop/cleave, including monks hands. As for the ore, I believe you can just use the "smash" command and it doesnt care if you have a weapon. If you want to skin stuff, currently I think that only works with Yarbok's knife.