As I understand it, you are concerned about children you will be working with. In that case, I think you should be mindful and respectful of the children’s parents, who may not wish you to introduce their children to the world of family discord. I know I would be very upset at a teacher or caregiver who did something like that with my children, no matter how gently she tried to do it. In most cases when working with children, anything about your personal life should be out of bounds. You don’t need to make children you work with aware of this personal issue at all, and in my view you definitely shouldn’t introduce this to them.
Here’s an easy way to deflect all such questions from small children. (You did say small - this may not apply as easily to older children). Small children are basically self-centered. If they ask if you are visiting your mommy and daddy for Christmas, you say “Oooh! I love Christmas and can hardly wait! How about you? What does your family do for Christmas? Do you visit anyone?” etc. That is, just reflect enthusiasm, and ask them the question back about themselves. Most small children do not truly want to know about adults, and certainly don’t want to hear about the complexity of their relationships. They want to talk about themselves, and have an adult listen and care. If they ask “Does your mommy ever tell you not to do things?” (and I highly doubt a small child would ask such a thing), I would simply jokingly remind them you are a grown-up now, then again redirect the question back at them - “I’m a grown-up now. But you are not grown-up yet. You are still learning. Now what was it your mother told you not to do?” I don’t quite understand the context you are envisioning for that second example, but hopefully you get the idea. That might be a case of trying to stall or see if you’ll give them tacit permission to be disobedient, perhaps. Just deflect/ignore the question, and put some form of the question back to them.
It is not dishonest to deflect their innocent questions, and it is prudent not to overstep your bounds into areas that really belong to the parents.
I wish you much success and many blessings in your new job working with children!