@mons 

b) Going by the images I cut, I'm not sure there is a plurality of sources which would allow cuts that big. Furthermore, remove.bg only allows preview images of ca 500x500, so they'd end up blurry anyway in most cases.

I completely forgot about that!

Here’s a picture I made of the player in 250px and 480px.

You can see the result where the image has jagged lines around the neck and ears.

A 480px image looks much better. Maybe the image could just be increased to something between 384px and 480px?