Try wetting it, then applying conditioner. Apply the conditioner all over the ball of hair. Then, try to break up the ball with your hands. Once you get it slightly looser, apply more conditioner and brush.
I think only steaming/ironing is your only hope for that thinner stuff. Or, install it damp and with finish screws instead of nails and you'll be perfectly fine.
It's always best to use products that are specifically designed for human hair wigs—they'll have less harmful chemicals than your standard shampoos and conditioners.
If your hair is severely damaged, it will not be possible to get a color that requires pre-lightening, such as pink, without risking severe damage and breakage.