Both of my birds are flighted. I don't believe in clipping thier wings, you just have to be more careful of what they can get into. My tiel is 14 years old and very well behaved, my quaker is just over a year and gets into absolutely everything he can.

Regarding the teflon pans...I gave all of mine away years ago when I got my tiel. I have read a lot of stories about the fumes and just don't want take a chance. If they are that harmful to birds, I don't want to eat with them either. All stainless or cast iron in my house.
I hope the necropsy gives you some answers. I would want to know what happened also if it was one of mine. How long did you have him for? I thought about getting a love bird when I got my quaker. They're so cute.