It is a bit hard to sort out your post, but I will just say a few things...
- kids have alot of energy, and a wonderful purity about them. They are not necessarily "one with the universe" in the sense of being a sage, while they are playing. They are simply playing and being themselves, innocent...
- being a parent, means parenting. It is possible to influence kids, help them direct their energy , play with them, do projects together, teach them... It is ok for them to be kids too, and just play.
- a play space is a play space. If a play space is not defined, it can be disruptive to a space not intended for that kind of energy.
Define areas, set boundaries, teach and practice mutual respect of each other's space. Be patient. You are the parent/teacher/role model.
-children don't disrupt adult qi. Quite the opposite if you have a healthy perspective. One can learn alot from young people's innocence and purity.
- a play space is for play, a religious place is for worship and reflection, a shopping center is for shopping. If you don't separate them , you have a mess. I don't try to meditate in a shopping center. "The energy there doesn't support that." I don't consider it disruptive to me, I do my shopping there. I may not like the decor or commercialism, there may be room for improvement, but, it serves a purpose.
-There is a difference between big picture stuff and small picture stuff in Feng Shui. I am not an expert by any means. Just common sense. Some things are permanent about a place, some are temporary. A cluttered room is temporary. The house, the directions it faces, etc., is more permanent, with greater constant effect. The land and area is even more so.
-if I create a space for healing, it would have that purpose. I would teach my children to respect that space, and what goes on there. In turn, I would respect their play space, but again, guide them. I would keep the two separate. Your family responsibilities come first. Make time and space for yourself within that or outside of that.
I have always worked at home. I have a workout/meditation/healing space, along with always having a studio at home. I was home to help with raising my kids, and they learned to respect my work spaces, they had their own space, and they learned to mutually respect shared spaces. There was plenty of opportunities in a 24 hr day to get done with personal work and interests, along with being a responsible parent.