Quote - Are dependent parameters something like ERC morphs?

Yes. Now we can actually set them up in Poser using GUI controls, making things faster and more intuitive.

Quote - also what are the other new 6 figures included?

from the accompanying paragraph at the top of this page:
"The new Poser 8 figures are offered in four pairs of male/female couples with European features, African features, Asian features and Hispanic features."

Basically, it's Alyson and Ryan with ethnic morphs (the least exciting new feature IMHO, as it's really just 2 new figures).