Spoilers!
Here you have the answers to all riddles. There's a comment below, but it takes a while to scroll so I'm commenting to move it up:
Starter Pack: 1) ashes, 2) lightbulb, 3) smoke, 4) torch.
Rough Stuff: 1) shovel, 2) bottle, 3) dirt, 4) cactus.
Hot and Cold: 1) bowl and spoon, 2) fishing rod, 3) fire sword, 4) cherry blossom.
Wave Away: 1) flag, 2) forge, 3) vine, 4) message in bottle.
Ingenuity: 1) ice, 2) glass, 3) bottle of firewater, 4) bow.