Amberser wasn't joking with these two; to address the issue of Withered Rose, he had been researching how to resolve the negative impacts of the undead.
Withered Rose was of the most orthodox type of Lich, transformed by resentment and obsession, binding the Soul to the Life Casket.
Despite making whining noises in the Connected Dream Realm, once out of the dream, she would still be subjected to the erosion of her humanity by the undead body.
Both Hasting and Hales underwent Amberser's modifications, and although their Souls were experimentally crammed with many things by him, they were essentially still the undead.
Over time, as their humanity faded and their cognitive abilities declined, they were destined to become creatures that could only drool.
Unless Amberser found them some "obsession."
But such an act was pointless because Amberser wanted to solve the problem from its root, not just to buy time.