I started trying pixel art recently (I'm not an artist) and found using existing spritesheets as templates quite helpful to get the style, proportions, and poses I'm looking for. I am however worried about plagiarizing other people's work using this method.
I put together a quick transformation as an example:
Using the Earthbound character on the left as a template, at what point, if at all, does my character cease to be a derivative of the original?
1. Change color pallet, clothing, and minor linework. Different hat / hair.
2. Change face and minor body structure in hands / feet.
3. Remove shadow and adjust linework. I would add my own shadow outline here.
4. Squash character to more drastically alter the body structure and re-work linework.