jesus you’ve experienced nearly everything, how about new growth that means it’s getting enough nutrition right?
I spent a lot of time observing and learning about these things during the time I kept them. New growth does and doesn’t mean they are eating. I had some that never ate but had some growth of the tips of the arms. I can’t say for sure, but after talking with some other aquarists who were successful with these animals, we think they may be able to use energy reserves to do some growth even if they aren’t currently feeding. It’s a good sign, just not a for sure sign.
Kind of like how the human body can go for a period of time without eating but still be able to perform normal functions. With crinoids, it just takes a long time for them to starve (apparently).