Pretty sure it's not infukun, also didn't he leave MICA?
Not sure, he's still in contact with them i believe, its just that he's more freelance now. As for this costume, its possible this was a collaborative work, to me, it does look like Infukun's colouring style its just the dolls... line-art and figure? doesn't quite fit. Even us in the wiki are unsure who drew it, we'll need proper confirmation from the artists in question. Otherwise we're just as stumped.