Didn’t the cajun guy find the idol at the water well, but doesn’t know it’s an idol? The clue that Val has sent her to the water well on her side of the island.
Hmm. I didn’t think of that. You might be right.
After examining the screenshots you posted, here's my theory on where the idol might be hidden and why Val didn't (presumably) find it.
The (X) symbol--the one that equals "dig--on the clue is one of the symbols painted around the edge of the circular lid on the top of the well (in the top right of the screenshot.) But this lid isn't hinged to the well and therefore it can be rotated. So the (X) symbol isn't necessarily going to be aligned with the location of the idol, because the lid is being removed and replaced whenever folks are accessing the well and therefore it is turning randomly as a result.
That's where the other clue symbol--the one that equals "water"--comes in. This symbol is also visible on the lid of the well (looks to be under Dale's elbow in the screenshot.) I think that if you align this symbol with the with "water," then the (X) symbol will align with (or point towards) where to dig. So how do you align the other symbol with water, when the lid is sitting on top of the well? My guess is that if you rotate the lid so that the symbol is closest to the ocean then the (X) symbol will be properly aligned.