I have beaten the game and for what I can see, those shops are just there for decoration (I know, thats lame). That unless some downloadable thing activates them in the future but I don't think so.
Before the Match with Zeus, go to the hospital with Domon (Bobby) in your party, some backstory will happen and then he will join you. He is at level 40 and has one technique of each type (except GK techs).