Some corrections:
- You dont need Dive or the Dive tool as you just need to wear the Greninja outfit to dive down.
- The weights have to be between 100-200, between 200-300 and 300+.
- You dont have to beat the Wastelands pokemon in order and the Noctowl only appears once you beat 6 pokemon.
- Before you are able to dive down you have to find 6 hidden pokemon and talk to the Sailor again.
- Before getting the pokemon for the weight-requirements I would suggest to beat all the trainers as a full team will make it easier to beat the trainers.
- Talk to the Golem after beating the Charizard-X-Boss to receive the Gem.
- From what I have seen the levers cannot be just any small object like random mushrooms or bushes but only rather specific objects like the tombstone, pumpkin, skull, axe on stump, mushroom on stump, dead tree, berry bush, sign etc.
- You dont need to use the sign to teleport to the Forest Master, that will happen after interacting with the third lever which is random for everyone.
Other than that pretty straight forward guide in textform, thanks for sharing.