In case others might find this useful, I created a UML diagram with a subset of the classes used for Mass Replication:
I highlighted in yellow the classes that are crowd specific. In theory if you need to use Mass Replication for something other than crowds, you just need to create new versions of all the yellow classes.
If you want the source it’s here: Mass Replication UML.vpd - Google Drive
You can open it in https://online.visual-paradigm.com with a free account.