I thought of something else, Stuck. This is making a statement that you are moving forward in your life "as if" she was no longer a part of it. Make some new pictures of you and the girls ASAP. Then take down all pictures that have your W in them. Don't have any little "keepsakes" (out in the open) that hold a special memory of your M. It is like you have wiped her completely out of your life. May sound a little harsh....but it is for a good cause. Just like turning your home into a man cave......will hit her....seeing pictures of you and the girls WITHOUT HER will shock her. I know that you aren't suppose to do things just to get a reaction from her....but I think she needs to see for herself how your future could look without her in it. Just like you dating.......these pictures and the man-cave will make a statement that you are moving on!
I'm sure you have thought of this already, but I would suggest that you leave the girls' room just as it is. Well, I guess it will depend on whatever your W leaves there for them. I hope she will realize that your 6yr old would feel more stable if her room stayed the same....but do what you can.
I would not remove pictures of their mother from their rooms and in fact, I would make sure that there was a picture of her there. Just don't want to hurt them with that particular thing, you know what I mean.
The 2yr old is too young, of course, but with your 6yr old, you might include her on some of the minor changes around the house so it won't be like a big shock when she first sees it after W moves out. She will feel like she had a part in helping daddy decorate the house and she'll like that. I know you are going to make their time with you very special. Not that it matters or not, but I'll bet that 6yr old will be talking plenty about what all they do when they are with daddy!
Once your W is actually out of the house, then you may even feel somewhat free in a way. I bet your mind will be able to focus on GAL more. You deserve it.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!