Thanks for the list, it was very helpful! I've already fixed some things in the update. The idea of making the traps impact thirst is great! (There's actually one that does, but it's pretty hidden. I think I'll expand it to others as well.)
Regarding the names of the dolls, absolutely yes. I don't know why I decided to call them the same, it must have been madness.
The "Actually in one of the acts I had two girl dolls in my inventory and neither were of any use for that same act." however, should not occur.
You get the Igel's doll by finishing the recipe. Ery's is in the mushroom room. Areth's is in the room with the amulet. The room with the amulet is unlocked by finishing Act II, and Act II can only be finished with Ery's doll. This means that, when you have two dolls in your inventory, it can only be Igel and Ery (Act II) or Igel and Areth (Act III), and one of the two will necessarily be needed for the puzzle. Do you remember how you ended up in this situation? Did you have to reload an earlier save?
The cholesterol metaphor is wonderful and I will use it again.
Thanks once again!