1. good catch! this was a change I made pretty late in the latest build (initially read as "PRESS", not "HOLD")- I'll patch this ASAP. sorry about that one! glad you could figure it out..

2. the operative clue here is "the map and the territory"- the sandy spots in the "smaller" island (on the screen with the anagram) actually also contain paths off of it, and if you extrapolate that map to the larger island, you can discern that the secret path is on the bottom-right corner of the island.
granted, i initially referred to "the territory" in another place, and i've had issues with people misunderstanding what "map" meant already. so the hint on the slab might be too vague... I'll think about it!

3. the logic for the final sequence of words is:
- "VA" is blue - spoken to 2nd keeper only
- "PO" is magenta (the color which blue and red mix to in RGB colorspace) - needs to be spoken to the blue and red keepers
- "R" is rainbow - needs to be spoken to all keepers
- "ES" is yellow (the color which red and green mix to in RGB colorspace) - needs to be spoken to the red and green keepers
- "IN" is green - spoken to 3rd keeper only
technically, by this logic, "R" should be white (since that's what red, green, and blue mix to), but I went with rainbow since most other text in the game is white, and rainbow maybe hints more towards the meaning of color in the other arrows.