Also, would the light in a fan/light combination be bright enough to act
as
the primary light source?

if by primary you mean sole light source, i think not. not necessarily
because it isnt bright enough, but because its probably not in a good
location. better to also have lights at the mirror itself. keeps the
ladies happy. its also nice when you need to fix/clean something in there
and can brighten it up real good instead of working around your shadow.

randy