Akane: Door-ju (Door Gun, literally), it can be used as charging attack by opening and closing the door repeatedly.
Karin: Kuuga (Pegasus) Bowgun, Kuuga Pegasus accuracy is top notch lorewise, it can shoot enemy moving at high speed (like Clockup speed)
Asuna: Hee-Hackgun, basically a flamethrower that can also turn into watercanon.