Can you guys make the Grease Pencil more physical, than be a ghost?

The Grease Pencil acts more like a ghost than a physical object, and I would like it if it was more mesh-like.

1. The Grease Pencil can't cast shadows, I had to do a whole Geometry Node sequence, just so that the Grease Pencil can have a shadow. (Images 1-4.)

2. Can you give more depth to the Grease Pencil? Because it cannot be seen behind transparent material, with the 'Transparent Overlap' off. (Images 5, and 6.)

3. I don't know if this is already a thing, but how can you make the Rigs have onion skins? Because, I couldn't find a way to, even the Grease Pencil onion skins didn't work. (Because my rigged character is a Grease Pencil.) So is there a add-on for that? If so, what is it? (Images 7, and 8.)

But, the moral of the story is, can the Grease Pencil be more physical, please? Thank you, for your time.