Breaking expectations in Ghosts of Saltmarsh (spoilers)

[KorvinStarmast]

I'm not sure you understood what I was going for. What I'm suggesting is to shift "the truth" to the lizardmen acting on the side of the sahaugin. The people of Saltmarsh will have had little or no previous contact with these lizardfolk, so the information gathering will be starting from zero. It's possible that the player characters can figure out that the lizardmen are working for the sahaugin under duress, but that will still make for a very different adventure (especially for the players that have metagamed)

How much extra work do you want to make for yourself? Having the lizardment as the cats paw/patsies for the Sahaugin creates a need to rewrite the entire relationship map between factions.

If that amuses you, go for it and do great things.

As you noted, increasing the participation of the sea elves (or even other elves local to the region) is a way to balance this out.