while the dragon is a bit more of a mystery, 0:30s should be beyond a doubt Kakita so I'd be inclined to say he did from 0:09 - ~0:42 at least - could be more

edit: just saw https://www.sakugabooru.com/post/show/114765

which was confirmed recently by an insider, so the dragon is 100% Kakita, his early work was massively slept on