Bundles are a great idea but it is way too hard to get when its suppose to solve early game inventory problems. I can beat the game before i can get 6 rabbit hide. Rabbits are hard to find, they're not that common, and hard to kill because they're fast and small. Even if you do kill 1 or 2 there is a high chance you wont get any rabbit hide. For that reason i think its reasonable to change the amount of rabbit hide from 6 to 3 and have the recipe shaped in a V with string in the middle or top of the V.
Copper is at most just for decoration, and while thats cool and all, but for the people who dont want to make a house out of copper, give the copper more uses like changing the recipe of the blast furnace instead of using iron ingots it uses copper ingots (Iron already has so much recipe using it anyways).