Yeah, don't do anything crazy until you get the test done on the dead snake, it could turn out to just be something that one snake had. I am very sorry for your loss and hope you can figure out what has happened soon so you do not have to worry!
And maybe its just me, but I would absolutely never freeze a snake, no matter the state it is in. I have money I have saved in the bank just for my pets, I would have them euthanized, I have had to freeze tarantulas in the past and even that isn't pretty, as soon as they start to feel the cold they twitch and make terrible positions and although I know they do not feel much it is hard to deal with, I would never freeze an animal with a spine.