Retopo is only partially usable for Poser.

What do you do with opening - closing mouth? Eyelids?
What about inner mouth? Teeth? Eyeballs?

Retopo is a new mesh in need of a uvmap.

JCM's and other exotic old school hacks are not an issue. Learn how to paint a Weight- and Bulge map, and they are a thing from the past.

But? And here come the catch !
How are you gonna safe the obj file? => This is a deep question for insiders.
Build the groups in Poser? => Same deep question for the same insiders.