I really like your pattern. The mint and gray is really pretty together I do not care for the orange it's just to strong and it completely changes the feel of the quilt.
If this was a commissioned quilt would you just change it because you thought it needed it? The client should always have the final say even if the client is family and your not getting paid. You did agree to make a quilt for her in her colors. Once this is done you can make another quilt for your new grand baby in any color you want. It never hurts to have multiple baby quilts and blankets.