If they're going to be based off anything, it needs to be Strife. And there's several reasons for this.
-Strife sprites are just naturally slimmer and more slender than Doom's. This provides a great base to work with, since females (or at the least, the females we're trying to emulate here...) are slimmer and more slender/curvy than the Zombiemen are.
-Strife's enemies hold their weapons more "realistically," or at the least, they hold them by their waist, which allows their chest to be shown more than the Zombieman/Marine's "I hold my gun across my chest" bit. The main thing here is that the chest 'needs' to be seen, because--and I *really* don't want to be seen as sexist, or anything--but the females obviously need to have visible breasts in order to more readily identify them as females.
The other big thing is, I think the females should thematically have a different design than the male marines. For example, the male marine's chest armour basically covers his entire chest. What I'm seeing for a female would probably be closer to this:
Ironically enough, I can also see the ab-hole in the titlepic armour (which doesn't show up 'anywhere' in the game) being retained for the female design. It'd help to further distinguish the two.
