If you think Wakasa Rumi is not Asaka , I will tell you a very invisible hint and I don't know whether or not you will be satisfied with it .
Then Asaka would be a womanly man right, like the chef/the one likes tea etc/the one who makes great sandwiches/one who has a ponytail.
But I guess there is something you can agree, that Asaka is pretty tall......Given the lens of the camera was parallel to the ground and it reached up to Asaka's shoulder, I do think Asaka would be over 6 feet height, too tall to be Rumi.
Regarding Wakita, it's very likely that he is someone sent by Gin but knows Wakasa Rumi's game-plan, ("Hence this one is quick witted.")
There is another link that, both Mary and Gin utter the same quote ("The demon in the darkness") to describe a hidden and imminent danger.
Mary was describing her drugger (Vermouth and her identity theft of Tsutomu and how Conan's voice changer made her think of that horrible experience.)
Gin was describing Mouri Kogoro (How he was involved in a number of cases which involved BO but later turned out as someone not involved, from a BO perspective.)
But this is a novel quote, Gin as of now didn't show much of a proclivity of using quotes, so did Mary.So there could be a person common to both Gin amd Mary's life who can have a lasting impression on people by his/her usage of apt proverbs to describe the situation.
Tsutomu Akai is such a person.....
Wakita's gate up is Rum's imitation.......
His name is the anagaram of Japanese version of Rum's pet phrase........
Wakita (unlike Bourbon) only wants to visit Murder scenes with Kogoro.....(as if his true target will reveal themselves at a murder case scene.)
Regarding the Yaiba hint (it wasn't a direct hint. The hint was about a very-close associate of the boss will feature in the show. So Wakita is compared with an actor playing the role of a villain. Unlike Bourbon/red-guy/Boss of some association etc.)