Actually I don’t think any trooper’s armor really needs to be changed. But it would make most sense to me if the stormtoopers were white, while the scout troopers were camouflaged.

For the stormtroopers I fully agree with before mentioned points:

Normally they probably want to be seen in masses for intimitation tactics.
In this special case (a trap) they ARE absolutely hidden until the right time, no matter what armor they wear.

Now for the scout troopers it’s different. They are not meant as intimidating mass force but have a special job: scouting unknown, maybe even enemy territory. For this special job it’s obviously a disavantage if you are easily seen by the enemy…