Sick peacocks. Columnaris?

I have 2 eureka red peacocks that aren’t eating. One has a distended/swollen jaw and looks like it can’t open its mouth properly. The other looks like it has a slightly swollen throat and is moving its mouth in and out in a weird way, but can still open it. They’re both lethargic and way less active than usual too. I’m wondering if this is columnaris or something else. It doesn’t have those external white fluffy spots but could be internal only.

I’ve moved them to a makeshift hospital tank (a 50L plastic tub) along with a 3rd peacock because I couldn’t tell which was which when I was catching them. The remaining fish all seem fine (4 yellow labs, an OB peacock, a venustus, and a yellow tail acei). I’ve dosed the main tank and the hospital tank with a general remedy (Mafenide HCl, Aminacrine HCl, Malachite Green; antibiotics aren’t available for fish in Australia)

Is there anything else this could be, and is there anything else I should be doing?