Nah, I'm pretty sure the best way to help her people is to destroy the empire that totally obliterated their bunny land. This new emperor is the same one that vanquished the bunny country. It's highly unlikely he would now suddenly help those same people, at least more than nominally. As soon as Tyuule asked for something that's not directly related to Zolzal's own ambitions, a greedy narcissist like he would immediately start to suspect her. That would be the beginning of her end. To be purely theoretic, even if he did do a 180 turn and tried to help the rabbit eared people, a majority of them would never forgive and even less trust him. If someone like Pina became the ruler of the empire, there's a chance she could give back the land to the bunny folks, free the slaves to allow them to return there, and grant them total indepence. There would still be helluva lot of bitter bunny people who would spend their days dreaming of revenge, but it might work in practice, more or less.
Tyuule would gain absolutely nothing for her own people by genuinely working with the emperor unless she somehow actually tricked him into believing freeing the slaves and granting the bunnies their own country would help the emperor and the empire. That seems like a 1% chance. Not to mention she's already so wicked it would be difficult for her to forget her own bloody thirst for revenge.