The article only calls out the "Acting" and "Writing" categories, and the language suggests they are mainly concerned with a human doing the actual substantive work. So in this case, stunt work that is duly credited will probably still be eligible, even if they alter it as you suggest. The whole point of stunt work is to have a stand-in do it, but have it look like the main character in the final product.
Even before AI ate everything, a lot of visual effects have been created with CGI, and they still gave out Oscars for visual effects.
86 96