About Weedle looking like Sewaddle without a leaf? Well, the creators decided they wanted to re-make a Generation I pokemon, so they opened a trans-vertex portal to warp their original Weedle design to them. On the way through the portal, it crashed through a tree.
Ow! Ow! Ow!!! Watch where you're goin'! You just hit Maple, the Great Witch Syrup's apprentice!