I have a cupcake order this weekend and the theme colors are baby blue,white, and black.The frosting flavors ordered are Strawberry & Peanut Butter.

Any idea how in the world i can get either baby blue,white,or black frosting color from pink and brown without impacting the taste?Especially with black?

I know i can color the light pink a blue shade...but then there will be red strawberry pieces sticking out still.ugh.

I think you need to go back to the customer.

The best way I can think is to make fondant cutouts in the theme colours and not mess with the flavours.

Or else you use flavourings that don't add colour to the icing (no natural strawberries...)

I would personally leave the frostings as they are: pink and brown. I would incorporate the colors in the cupcake liners and fondant topper.
Strawberry:
1) Black liner/cup, pink frosting, white fondant star or w/e
2) baby blue liner/cup, pink frosting, baby blue fondant flower or w/e
Peanutbutter:
3) Black liner/cup, brown frosting, white fondant star or w/e
4) baby blue liner/cup, brown frosting, baby blue fondant flower or w/e

Could you do filling flavors in strawberry and peanut butter instead? Chocolate cake with peanut butter mousse filling and dark chocolate frosting (so dark that it's almost black) sounds really yummy!