Bagginsbill is still around. He answered my question about render settings just the other day.

Superfly is a more realistic renderer than Firefly. If you want photorealism, that's the renderer for you.

Me, I still mostly use Firefly. It's faster, sharper, and my style is more illustrative than photoreal anyway.

Snarlygribbly has some Python scripts to optimize settings for Superfly or Firefly, but generally it won't be a huge problem. Vendors often include two sets of textures, one for Firefly, one for Superfly. Sometimes you have to choose the right one, sometimes it automatically use the right one.

La Femme is included with Poser 11. She won't work in older versions of Poser, or in DAZ Studio.

RDNA is indeed toast. Many of their products are now for sale at DAZ.

Some of SemiDieu's scripts work fine in Poser 11, some do not. There's some issues with older Python scripts, just because Python has changed over the years. There's some workarounds, I believe, though I haven't tried them myself.