Oh heavens! Amazing. Fascinating. I started reading about hornet survival in winter. You probably know all of this, but it's new to me. Apparently, by the time you got to the nest, the queen was gone. All the hornets die except the queen. She looks for a place to hibernate, goes into diapause and waits for spring to come out and build a new nest. It is possible she found a nice cozy place in your attic to hide!!! I hope not.
Great pictures. The posing was a bit macabre, but they all died naturally, so why not?😅