Not sure I am understanding what you are saying about the closets. I do however see that you are planning on putting only one sink in the vanity. Don’t you think it would be wise to install double sinks considering it is a bathroom for children? The shower does look a little deep for the space. making it smaller would give you more room between the shower and vanity.

I'm not sure I'm understanding either, but what if you just flip the closets to sit against the bathroom wall. You would lose a bit of closet space but it would create that flushed wall look I think you're going for.

I also like adam powells deeper closets . . with built ins on the sides you can really make good use of the deeper space . .

Put a double sink in, rotate the shower to the outside wall and place the toilet next to it. Similar to the master bathroom.
If you need storage, place a linen closet to the side of the shower as the room looks wide enough.
Also slide your master bedroom door towards bedroom 3. It will frustrate you to have the door off center in the room. By sliding it towards bedroom 3, you can place a dresser, tv or artwork across from the bed.

Thanks everyone! Your recommendations are well appreciated! :)