Is that really Kuma and not Akagi?

Not sure. I only know his male Admiral got Suzuya, and chibi Shiranui.
No character tag in Twitter

It's hard to say that's Kuma. In my view that could be Akagi, since she is also wearing a red bikini =w=

Note that she also has shaved ice in her hand. So knowing Akagi and the fandom's portrayal of her having food at arms length, it just might be her.

Double checked the source myself. Someone also couldn't tell if it was Akagi or not. Artist confirms it's Akagi.

Can't help but think that Admiral looks like Nozaki-kun

Love his character design, seems to show influence from otome game’s style, both his male character and his female admiral.

And he got a third Admiral too, a queer and paired with RJ.

Yaoi bait Admiral.

It would have to be Akagi, since Kuma has a beary ridiculous and instantly identifiable ahoge.

But Akagi is supposed to have nice, straight hair, right? I don't see any sort of ahoge in the official art as well. But if the artist says it's Akagi, then it's Akagi.