Yeah... I noticed that most character animations were just similar FFD that could work decently for most of them. In the same time, my goal was to be able to customize them. It works perfectly fine if I export these characters as images. That already saves me a lot of time, so this technique does help and Spine is perfectly fine for FFD Pixel Art animations.
NONETHELESS, I don't want sprites if I can get the skeleton (who would?). Thus, I would need the mesh points snapped to the pixel grid in order to achieve the results I'm looking for.
Here is a small example. I put the character in an idle stance, and get the character walk animation. It works fine for skins (especially for multiple skins in order to choose torsos, pants, shoes, etc.).
Of course, if you could add a pixel art oriented mesh edit mode in Spine, that would be CRAZY. But it would already be more than enough with some runtime code to snap mesh points to pixel grid.
I'm also sharing with you this video to see the problems I find in Unity. Do you notice the small pixels and lines that ruin the final result? These may not be noticed if I zoomed out, however, as soon as I zoom in, the inaccuracies are noticeable.
VIDEO