Yeah I wouldn't color the foam either! The color could bleed out if you put pressure on the foam, and mixed with sweat, it just feels like a recipe for something not so nice! You never really need to put foam in a place where it can be seen anyways, and on top of that, the armor sits tight enough to the body that it will be very hard for it to be visible!
Regarding the boots, if you are aiming for Expert Infantry/Centurion, then the boots need replacing! The shins look great on you!