I’d actually go for Lawful Good vs. Lawful Evil imo She was content tying to convince them to leave according to the rules and systems they’re familiar with (Lawful) but once negotiations broke down of course she’ll enjoy slaughtering them all (Evil).
You are right.. Maybe he knew that she was strong/witch. Could be blamed on narrative not explaining it but I doubt it personally
in the wn, evil alignment corrupts the mind and behaviour to some extent. All witches had evil behaviour too. (all of them are invaders that kill people)