A touch late, but getting there nonetheless.
So, making a sketch from the thumbnail proved much more difficult than I had thought it would be, but I think I got something good enough.
The linework is actually two separate layers—one layer is entirely "vector" strokes, mathematically solved from a series of adjustable anchor points. It came in real handy for all the smooth curves on the tails! The other half, reserved for the smaller details and less regular contours, is still completely hand-drawn. I'm not so sure I blended the two together well enough, but it looks alright to me, for something I've only really ever attempted once before.
This time I wanted to handle (most) of the lighting work on a single layer. Sai 2 has a Shade/Shine blending mode for layers, which is literally just a combo of the two. Everything at a value of 50 and below darkens the image, and everything above that lightens it. Theoretically, I'm having the definition of shadows and highlights, but it really hasn't manifested in any obvious ways, so it seems fine. The left image is most of the light work blocked out, the second is after a second pass with a blending brush that's got a very thin, widely spaced bristle pattern.
Anyway, we're only half done here. I'm going to take a nap and finish things off when I wake up. It's been a long few days.