I'm making a lore-friendly version of the "Skyrim Monster Mod" - http://skyrim.nexusmods.com/downloads/file.php?id=9694.
My version (work-in-progress) is here - http://skyrim.nexusmods.com/downloads/file.php?id=16411
I'm making two main versions - one which is completely lore-friendly, and removes all creatures from the monster mod not seen or referenced in previous Elder Scrolls games.
The second version - which is where I hope you can help - is renaming creatures to fit better into lore.
My plans for renaming creatures so far are:
1) Treant - Any objections for renaming simply as "Spriggan"? Although all Spriggans in Elder Scrolls lore are female in appearance, they are inspired by the Cornish Spriggans (http://en.wikipedia.org/wiki/Spriggan) which are not exclusively female. Another option would be to rename as "Nature's Guardian" (an alternate name for Spriggan) or "Spriggan Patriarch".
I think I'm leaning towards "Spriggan Patriarch".
2) Werecat - I think I will leave this as it is. There are plenty of were-creatures in lore, and it could also be what the Nords call types of Khajiit they've never come across before (people name things according to other things they know, and they know all about werewolves).
3) River Naga - how about "Sjoormen"? (Norweigan for "Sea Serpent"). Otherwise just "River Serpent". Are there any references to sea serpents in any of the books in game?
4) Baphomet - rename as "Daedric Knight" or "Daedric Soldier"? Otherwise just "Daedric Minotaur". I'd like to leave the name as open to interpretation as possible. Which realm is a minotaur-like creature likely to come from anyway - Hircine's?
5) Lilith - she's a vampire, but has Daedric-looking wings. "Daedric Vampire Priestess" seems wrong - but I can't think of anything better.
6) Drowners - I'm not sure on even including these iat all. Possibly as "Ghoul" (as seen in Arena - http://www.uesp.net/wiki/File:ArenaGhoul.gif). Maybe can adapt as "Drowned Ghoul" or similar?
7) All Atronachs that don't fit with known lore renamed as "------ Golem", as created by mages (see Daggerfall).
As for the variations of Giant and Falmer - I don't have a huge problem with the Giants that I've seen in the monster mod - Fire giants are stretching things a little, but maybe they're just cursed in some way? As far as I understand, Falmer are snow elves that have devolved and gone blind due to their time underground with the Dwemer. It seems plausible that the varieties added by the Monster Mod are either various stages of their devolution - or maybe they had been experimented on by the Dwemer?