I don't think there's any such thing as topping from the bottom. There's dominating and there's not dominating. Submission is a choice that your wife may make, but it doesn't mean she's going to be successful at being submissive 100% of the time, and she's going to need you to be consistent and trustworthy. If you're having trouble with it all feeling overwhelming then just cut back.

Make one rule. It sounds like "No back talk" might be a good one. Whenever she back talks, make her regret it. Ignore her when she does, go to another room, do something to make her realize that it's not going to lead to either attention or fun time. At the same time, praise her and give her attention when she's been obedient. It doesn't have to be anything overtly sexual: nothing about having kids in the house stops you from giving her a squeeze and a smile, and whispering to her that you have noticed her being good. If you can get to a point of consistent punishment and reward with one behavior, I can pretty much guarantee that you'll see her behavior change. The second, third, and fourth rules will all be easier to enforce.

You and her should also really think about whether you really need "play time" in order to have a D/s dynamic. I would argue that kinky play (as wonderful as it is) is a separate thing. It can certainly be reinforcing and is great fun, but nothing about a vanilla life situation should stop her from being respectful and considerate of (and deferential to) you if that's what you both want from the relationship.