Im Chinese, well bleaching your hair is already harmful but if you want to dye your hair with noticiful effect you need to bleach before dying.
I dyed my hair blond, red, dark brown and currently looking for dark blue (which will only be seen if under the light) so ya, if you want to dye your hair that its brown and not black completely, you need to bleach before dying it which will make it (Brunette).
No, dying your hair wont make it less soft. (all, if not; most chinese peoples hair are soft naturally.