It seems like the Replace Mesh feature found under the Mesh dropdown doesn't work after the 5.05 update, and I've tried it in multiple projects with different characters. In previous versions, I'd do an OBJ export with Nude Character in Bind Pose, make adjustments as needed inside of Maya, export the meshes back out as OBJs, select the individual mesh I'm wanting to update inside of CC5, and run Replace Mesh and everything would update without issue.
However since the 5.05 update, this stopped working and it's become a big hinderance to my pipeline as I can't reliably sculpt and use my own tools to make quick and iterative updates. I'm hoping you can please look into this!