Ok, to make up for the really bad test render I first posted, I tried applying what RH has been saying to the scene:
1) Keep Camera AA Passes as low as you can.
2) Raise lighting samples, Refl. Samples, Refr. samples, and SSS Samples first, before Camera AA passes.
So, that being said, and I was getting frustrated, I rendered this image out @ 4x resolution, and scaled it to final size:

(Time : 2h16m39s @ 3200 x 2400; No Adaptive AA, 4 AA passes, 1 Environment light @ 25 samples; 4 / 2 / 2 Refl/Refr/SSS Samples)
(No Noise Filtering, Sinc Filter, Radius 3.0)
And things look wonderful.
(Note, it appears that render times scale pretty much linearly; My estimate of 2h40m was just a bit off the actual time, based on a 10m time for an 800 x 600 render with the same settings - I took the square of the resolution multiplier (3200 x 2400 is 16x the number of pixels of 800 x 600), times 10m)
So, I started with everything as defaults @ 800 x 600, and started with 25 AA passes / 4 samples on the environment light, and started reducing AA passes while bringing light samples up.

(Time : 14m27s @ 800 x 600, No Adptive AA, 7 AA passes, 1 Environment light w/ 16 Samples, 4/2/2 Refl/Refr/SSS Samples, Sinc Rec. Filter, Rad = 3, No Noise Filter)
After this point, fewer AA passes start to degrade the FFX fibers.
Things I have discovered
1) Denoiser shouldn't be used with FFX, it obliterates fiber details.
2) Adaptive AA incurs a fairly hefty performance hit in this example - about 25% longer. I thought AAA was supposed to help save us time?
3) FFX likes and needs AA passes; The lowest I would go is 6. After that things degrade quickly.
4) I need to work on making my fur textures stand out/come through in FFX.