Going off the reservation a little, since everyone is recommending Env Sphere and IDL, I would go more towards a studio setting and try to convey a sense of youth and innocence.That might help you out a bit with the "perv police".
Maybe a gymnast's outfit for the younger characters, or something like that.

You might have a look at LilFlame's Simplicity- IBL light set. It works very well for pin-ups and I'm sure they would work well for your promo's, and I think would give you a head start on some of this stuff.
I'd steer clear of Poser's AO, which Poser's IDL seems to add to a scene automatically. I don't know anything about the technical stuff, but to me, it just doesn't look good to my "brown eyes".

It's one thing to make a really large image look good, but quite another to make a small one look good.

Just a few thoughts, FWIW

PS: I wouldn't worry all that much about the hair. IMO, there are no realistic looking hair characters or props- at least not at the Poser or Daz level of CG.