Originally Posted by Lissy Longbottom

To change the color of the white part, I would make a plain fill layer of whatever color you want it to be and then set it to color or screen or whatever to get the color on the white area. But since you want it only on THAT area, be sure to hold down the ALT button and click the line between the two layers (as you hold down the button and move your mouse over that line, two little circles will appear on your cursor so you know it's working!) That allows you to set that color layer so it ONLY affects the mask layer rather than messing up the coloring of your whole graphic! You can do this will any layer - so if you have a layer you want to add a texture to and you just want it on THAT layer, it'll work for that as well, or only one layer you want brightened or saturated, etc.

As for the brushes - I usually make sure I only download brushes that are actual BRUSHES so I can't say for sure, but I believe the brushes will work the same way, yes