Thank you muchly. The streamlining of the introductory puzzle was necessary since it was never the intention to needlessly obstruct players. It acts as a soft tutorial and I think it's much more important to teach the players to explore, rather than teach them to look for obtuse secrets. Hidden pathways might be better used for extra secrets to reward curiosity, not so much to bottleneck progress in the tutorial area of the game.
Field studies are supposed to be unlocked entry by entry in the full game (when each one becomes a theoretical factor). They are never dumped all at once and there's not that many total.
The reason for the picture note is that Mike B is illiterate. So to make communication more efficient for when they might not be in the same place, they came up with a symbol system and started leaving each other notes in this code. It's never stated outright, just implied, but it might be mentioned eventually if it becomes relevant to the investigation.
Noted all the other stuff and thank you again!