So, I'm fairly new to the game, and I have two questions, to be exact.
1. I can't seem to find any sort of a light source. I checked the wiki, which mentioned a torch, but I'm not sure how to get it.
2. I'm having trouble with the third piece of the lizard statue. The game mentions a young witch, but I've yet to encounter someone like that. I did encounter the witch in the swamp, but I'm not getting any talk/task options.
1. You can build a torch in your workshop at home.
There are two other sources of light. You need to have 5 glowshrooms in your inventory to get one (you can only get one). Othra OR the Witch in Daytime will have a talk item about how to light up the dark, if you talk to either one they will give you a necklace that provides a permanent light source for the underground.
Each necklace has advantages and disadvantages, and once you talk to one of them the other choice disappears permanently. I prefer the Witch's Amulet myself.
2. The Daytime Witch in the swamp is the young witch. She has different tasks and talks and spells to learn and ingredients to buy from the Night Witch. She has a task to get a Lizard's egg from the breeding chamber in the Forgotten Temple in exchange for a piece of the lizard statue.
If the task is not in the Day Witch's task menu, make sure you have ended the Lost acolytes task and gone to the inner shrine, back corridor and placed at least one piece of the statue in the gate. Then make sure you have talked to Othra about the gate. It has been a while, but I think that is all you need to unlock the Day Witch's task for her piece of the statue. Though if Othra wants to tell you anything else be sure and talk about that too.
EDIT
I just found a day 10 save and yes, the task will appear in the Day Witch's task menu if follow those steps.