Yeah, Jin's MVC persona was more like a Go Nagi pilot from Getter Robo/ Mazinger merged with the lead from Apocalypse Zero(Kakugo no Susume). Usually he's a calm, reserved, soldier type that follows orders and a strong believer in Justice!
Not totally sure what you're asking. But that sailors' outfit Rikka is wearing is what she wore at the culture festival in the anime series she's from.
Oh, you're right. They are quite similar. But I pretty sure this is just your generic princess carry (because of a hurt knee), and using the outfit Rikka wore to the culture festival.