Is a skin like discharge after a colposcopy/biopsy normal? would oral or anal sex be ok?

Very likely, yes: The stains and medicines used during colposcopy cab result in a dark brown discharge. This would not effect other forms of intimacy.

Not unusual: It is a biopsy so some small amounts of tissue or inflammatory material can come off. There may have been a thick coagulant involved which is coming off. Non vaginal sex should not affect the healing process of the cervix, should be fine.