...

It is yoo early to tell if she is good or bad for the children but I think she will slowly use them to manipulate MC's position as the head. That is what the swordsman uncle's objective is, clearly. In the past, she didn't trust them not to step all over her so she didn't let them stay. This time, being wiser, she hopes to stay ahead of their tricks and do what is best for all the children.
I really hope the aunt is only there for moral support. And I like the way she is drawn too: a kindly, graceful chubby instead of the usual "I'm so obese because I'm either bad and/or ugly or in need of a weight loss arch."