Uma attempts to transfer all her knowledge of controlling lunatics.
The secret is to get them dependent on your approval. Once they're dependent, you can provide swift and certain punishment for misbehavior and intermittent reinforcement for good behavior, always leaving them craving more approval than you will give them. Also, if they have any little hobbies like rape or torture, make sure you give them adequate scope for their impulses in ways that don't hurt you. The "get them dependent on your approval" step is of course the most difficult; Uma is acutely aware of how much of her position is secured less by her own decisions and more by Harry's past whims.
Uma is also, clearly, achingly jealous. Her mother's name has done nothing for her, less than Gaston's for Gil, and she resents it. Her mother humiliates her in front of her gang. She waits tables as if she didn't earn as much through protection money as her mother did through the restaurant. Maleficent and Grimhilde trained their daughters to leave the Isle and take over the world, and everything Uma knows she taught herself. And now she's not going to leave the Isle because of her mother's name. She is helping Alida, but she hates her.
Uma daughter of Gustav wouldn't have a gang, any more than Alida daughter of Gustav does. Uma waits tables because she is far more frightening living with her mother than she would be if she didn't. This is not the sort of thing that would ever occur to Uma, when she's thinking about how mistreated she is.