If you're at 124/130, you're missing 6, and the only single source of them which is 6 is the large animal fossil in the field office. However, I assume you already have that one as it'd be pretty obvious if you were missing it. As such I'd expect it to be more than 1 hint, unless you're missing all 6 from Journal stuff, which seems near impossible.
The only journal thing worth more than 1 is indeed the Mermaid puzzle, worth 5. I'd do that puzzle again just to be safe, you never know, I certainly know that I've done things only to have them wiped out when I unexpectedly quit out of the day for one reason or another. Beyond that, I'd keep checking back for other hints.
Golden Walnuts are the currency of the parrots on Ginger Island. The number of Golden Walnuts that a player has saved is displayed directly underneath the Player's name in the Skills Tab. Walnuts are shared amongst players in Multiplayer.
stardewvalleywiki.com
Journal Scraps are collectable pieces of a sailor's journal that can be found on Ginger Island. They contain clues about solving puzzles, collecting Golden Walnuts, and general information about the island.
stardewvalleywiki.com
I checked the scraps - 1 clearly isn't pointing to anything. 2 refers to ones which can be gotten by fishing, but the parrot hints "
[Quantity] deep in the water... " which is clearly the hint for those ones. 3 talks about ones in trees, but you indicated you checked those, and besides which I somewhat expect those to be included in the "
[Quantity] hidden in the north..." hint. 5, 7, 8, and 11 talk about the forge not Walnuts, and there are hints for any in the Volcano anyway. You already have 4, 6, and 10. I don't see how the evidence could point to anything other than it being the Mermaid puzzle.
