So I made some research about these two unknown character (I tagged them already).
It's a joke about Akagi and Kaga's name which are the same as Akagi Gunma from F and Bleed Kaga from Future GPX Cyber Formula
Both characters are voiced by Seki Toshihiko, and both manga/anime's theme are about racing car (which is why, Admiral Makoto is talking about cars).
While Kaga from KanColle and Bleed Kaga are written with the same kanji, Akagi from KanColle and Akagi Gunma are not (and this is why, Shigure said that the kanji are different).
Akagi (KanColle) => 赤城 Akagi Gunma (F) => 赤木 軍馬
Admiral, are you drunk?Yo, Hayato!Makoto just noticed it!Whoever that might beThe rest is omitted!!But if there is Seki Toshi〇 then we can run the car!! He can run 2 cars by himself!!Makoto is still underage!This is 「Kancolle」, not a car.That if there is Seki 〇hiko then we can cover the cost for Akagi-san and Kaga-san.The characters are different too. It's not Akagi, but Akagi.
赤木 cf 赤城, one for "tree" and one for "castle"