Yeah, the White-Fronts aren't very common at all, and especially not the Lesser WFA. Any of the ones I've seen in person have been at least twice his size with different green.
He seems to be alright right now. He started having a lot of blood in his stools about a month ago today, and I took him in to our Avian vet on an emergency basis at 9pm. I'm still waiting on pathology from the second endoscope, but we are suspicious that it may have been a trauma event or is a tumour. How he would've hurt his kidney, I have no idea, but the vet says she's never seen anything like it.
I did at one time work at our local zoo, but decided not to continue after a year there. It was too much of a health risk to my two at home. I would take my clothes off in the front door and shower before going anywhere near them. It was loads of fun working with the birds, but it also meant a ton of interaction with the public due to the open access to the aviaries.