A, is good but I don’t like the brown fur (I would try grey or blue), grey around the face/chin (I would darken it with black or a dark blue), and stark white of the ears (needs shading, a thicker line, something to add visual weight). I like the overall composition best, just needs tweaks.

B, I love the contrast and unified feeling of the lemming and background. I wish he had a clear helmet. Best choice IMO.

C, not enough visual distinction, especially as a smaller size icon. shape, detail and color pallette too simple for me.

This is why it makes sense for communities to not all pile into one instance, it gives one instance admin too much power and responsibility over everything.