Nah, I used to do it in nifskope. But I also only did simple things like the eye trick where I at first moved the bone in the nif, then reimported and exported the nif to / from Blender again and again (normally, things work after 2 or 3 iterations) while always checking the result in nifskope with added animation till the whole thing works. Then I open all the kfs and correct the bones coordinates according to what I set them to when working on the nif. Yet the problem is different: the cause for the eyes issue was, that they weren't lined up with their bone. The fingers are lined-up well, yet the animation doesn't fit 100% to the body shape, I guess.