Don King is a reference to Mike Tyson's coach. His design is based on Durden from Planet Tyler, both of which were featured in DekaRangerepisode 26 which both had fight clubs.
Planet Tyler is a reference to Tyler Durden, one of the protagonists in the movie Fight Club.
Though his face is not shown, it's implied that Kaguragi has a meeting with Captain Marvelous from Gokaiger.
Aihab is a reference to Captain Zeihab from Gingaman who in turn is a reference to Captain Ahab from Moby Dick. It's also possibly a joke on how her name sounds like "I have" while Zehab sounds like "They have." The character appearance appears to be based on Shellinda from Gingaman, perhaps implying that she's the child of Zeihab and Shellinda.
Don King is voiced by Hayashi Tsuyoshi who portrayed DekaBlue on DekaRanger. When Prince wins the match, he calls him "a super cool" and "perfect" partner, a combination of DekaBlue phrases.
Gallery
Riki and Dorin
Aihab
Don King is a fellow Tyler seijin like Durden from DekaRanger 26