Answers which are not related to the question such as repeated attempts at trying to escape their bonds or vows of vengeance for the torture and deaths of family were not included and made up the bulk of the answers.
The remaining combat effective sorcerers and witches were used to communicate between members of the cult and the salamanders.
Answers in parenthesis are answers derived from their assumed true answers based on your experience as a cult leader and some mind reading.

Is a ceasefire possible?
Dumb Sal: Screeching noise.
Smart Sal: Yes. (I would like to stop being in prison awaiting a slow and torturous death or worse)
Smarter Sal: When the first of us changed we saw that we were kept in pens and cages. There is no reason expect a better treatment now.
Notes:
The smarter salamander is not wrong. Given the cult xenophobia, a slave caste that undergoes brain modifications to render them compliant or extermination is a good assumption.

Where are you from?
Dumb Sal: Some more screeching noise.
Smart Sal: Egg chamber.
Smarter Sal: We escaped from your jails.
Note:
The mutated salamanders came from the Menagerie. A hybrid lab and animal pen for interesting creatures captured by the cult.

Want to be friends?
Dumb Sal: Even more screeching noise.
Smart Sal: Yes. (Is this the option to make my life less awful?)
Smarter Sal: We will not be your slaves. (Same.)

Anything to do with Avignon?
Dumb Sal: Yup more screeching.
Smart Sal: What is an Avignon? (No idea.)
Smarter Sal: I do not know if your foe had anything to do with our creation. (Same.)

Note:
Ripping through some memories and causing some mild san loss. It seems like the mutated salamanders were drawn to this place by that crystal. More memories show that it enhanced their intelligence further and most likely imprinted rudimentary knowledge which seems to include tactics and strategy.

It seems the smartest of their kind realized that the cult would return to enslave them one day and prepared for it. Use the time while they were thought of as a mild threat to propagate and when the serious force (yours) comes inflict enough casualties for them to pause to call for reinforcements (you did) and start escaping. More inane thoughts were not included such as living on the fringes to be hunted down is still better than having your mind shackled and used as a pet.