1. The shears and flint & steel
Most people don't notice it, but I did. Iron requires at least a stone pickaxe to mine it. But Jesse has a wooden pickaxe in the montage (which I assume broke because Jesse then starts using his/her hands to break everything).
2. How does Petra go to the Nether?Petra seems to go to the Nether to get items for people. But to mine Obsidian, you need a diamond pick. Petra has an IRON pickaxe.