[X] Buffy rejects Visser Three's offer, saying she'd rather not get directly involved in the war between the Yeerks and the Andalites. He'll probably be pretty angry, but what's he really going to be able to do? She won't tell Elfangor about this, and she'll still have a non aggression pact with the Yeerks.
[X] Buffy pretends to accept Visser Three's offer, but goes behind his back and warns Elfangor, backstabbing Visser Three and traitorously breaking her non aggression pact with the Yeerks. She might be able to keep her perfidy a secret, but then again if things go the wrong way it could be hard to hide. You'll work out a counter-plan with Elfangor to kill Visser Three and maybe even free Alloran.
[x] Buffy accepts Visser Three's offer and follows the basics of his plan to trap and defeat Elfangor; you'll have a chance to iron out more of the details when the time comes. She won't tell him about her secret meeting with Elfangor or about Loren though.