Preparing the character for animation in AE

Hi there. I have searched the whole YouTube and the whole internet with only one goal: to draw the human character in separate layers and prepare it for animation in After Effects. Sounds simple, right? But it isn't. I found just one tutorial which was partly helpful for me (that was "2D animation 101"). My problems are following:

1) I want to draw character with outline stroke with darker color of main color (for example, if I draw face and coloring it with some skin color, I want to outline stroke be darker version of that skin color) - problem here is when I draw body parts in separate layers, my outline stroke doesn't fit perfectly in the place of connection of two layers (two body parts), which isn't acceptable for me. Note that I use variable width option.

2) When I connect body parts (separate layers) with perfect circles (joints), my rigging in AE doesn't look good for sholders and hips. I would like to see some tutorials how to connect sholders-arms and legs-hips with joints to my rig be just perfect.

3) I also want to my character has shadows on all body parts. As I know, shadows must be drawn as separate layers too so they can be manipulated in AE. Does anybody knows how to draw shadows as separate layers to match perfectly on all body parts (with outline stroke still visible after adding shadows layers).

ANY KIND OF HELP WOULD BE VERY VERY HELPFUL TO ME DUE TO I WAS LOST FEW MONTHS UNTIL NOW TRYING TO FIGURE OUT WHAT IS THE RIGHT WORKFLOW REGARDING PREPARING MY CHARACTER FOR ANIMATION!!!

THANK YOU IN ADVANCE!