That probably seems like an easy question, but bear with me.
Short version:
Can I disconnect part of a mesh and then reconnect it without destroying the UV, vertex groups, existing shape keys, poses, and armature?
Long version:
I have a model that I’ve been working on since I started learning Blender. Now she has multiple hairstyles, vertex groups, shape keys, poses, and the perfect armature and weight painting. I’m now working on her facial expressions, which I’m doing with shape keys, and perhaps bones. I am sculpting one side of her perfect face and I’m trying to mirror it so I’ll have the same sculpt work on the opposing side. Problem is, I’m realizing now that my mesh is not symmetrical. It’s close, but not perfect. So, when I go to mirror the shape key, I get an abomination. I’m wondering if I can disconnect her head from her unsymmetrical yet still somehow perfect body, make her expressions, and then put it back without a list of consequences.