I think it could be reasonable to have separate "fandoms" for all drafts (or Silm + drafts) and the Silm on its own. Even in the non-Lost Tales HoME there are some wild variations from the easily-accessible Silmarillion and, especially in an exchange like this one, one wants to avoid mismatch. On the other hand, I feel like it might be fine to put Hobbit, LOTR, and Silm in one category since it seems unlikely for there to be conflicting understandings of the same character/request, even if people might just be interested in one chunk of it.