Regarding Zhane Masaki's edit of this artist from "M. Nakagaki" to "Masaki Nakagaki," I want to point out that that's
probably how his given name is read, but as far as I know there's still no concrete proof (although I haven't done any research on this in a while so maybe something turned up). There's a Masaki Nakagaki who's credited for a "Pyramid Magic Medley" on
this Radio DC episode recap. Pyramid Magic is a Genesis game, just like Nakagaki's only confirmed work, Phantasy Star IV, so in all likelihood, that's the guy. Pyramid Magic unfortunately doesn't have any end credits to verify that, but this is on an official Wave Master page.
(Someone should check through these recaps and see if there's any useful information in them. In the one I linked, I see a specific track composition credit for Skies of Arcadia, whose OST as far as I know doesn't break down which tracks Minobe and Maeda composed.)