The word 'rouge' is a common noun unless it is used for something specific, such a Baton Rouge, Louisiana. It is not a collective noun; an appropriate collective noun under which it might be found could be makeup or colors.
The word 'drama' is a common noun, a singular, common, abstract noun. A collective noun is a word to designate a group of individual people or things as a single group such as a crew of workers, a...
Yes, a collective noun is a common noun unless it used as a specific name or title. Examples of collective nouns used as proper nouns: club, The Friars' Club, The Boys' and Girls' Clubs of America...