I think that Gorcrows should be removed from the mod. While the poems themselves found in The Adventures of Tom Bombadil are canon poems written by Middle Earth writers, the characters, creatures, and locations found within them are not real within Middle Earth. Their names are real as fictional ideas that the in-universe writers came up with, but they really are not real in Middle Earth. The red book is more like an ancient historical text. Middle Earth Orcs and Trolls are fictional to us, but real in Middle Earth and may have inspired things like the Mewlips. Not every thing mentioned in Middle Earth is real. Sometimes things are made up by their fictional writers. We see this in real life. Tolkien made his fictional universe truly believable with the Adventures of Tom Bombadil as the book gives us an insight into the literary culture and history of the Shire.
In the first two poems, it is clear that the hobbits of Buckland know folklore of Tom Bombadil dwelling in the Old Forest.
Were-worms also should not be added to the mod as they were only mentioned in the Hobbit, which really should not be taken seriously because of Bilbo’s unreliability as a narrator. He could have made them up along with the last desert as we all know what his poems are like (Errantry). The last desert should remain as it appeared in a Middle Earth map.
Also, the three trolls and the talking purse are likely Bilbo embellishing certain details for humor. After all, those are the only three trolls in Tolkien’s Legendarium that actually speak. Though we see two other talking trolls in the adventures of Tom Bombadil, but they, like the trolls in the hobbit, are also products of a Hobbit’s imagination.
To add this literary culture into the mod, I suggest that maybe some Hobbits could maybe quote lines from these poems or even make comments about them, maybe even review them.
Speaking of reviews, this would open up the possibility of lore-books being added to the mod where the author reviews and critiques these poems or analyzes them. I would certainly enjoy reading things like that. Maybe certain lore books could be retellings of some of these poems similar to how in real life people retell fairy tales in different ways.
