Given the prevalence of the term ‘the void’ elsewhere in the Books as a general term, as well as in places like Ghost Fragment: Fallen 4, probably not. Calus seems to recall a ‘wall of perfect void’:
The Leviathan came to a halt before a wall of infinite void. It could go no further, as the navigation system had suffered a cataclysmic failure. The course that the conspirators had set crossed a space that simply didn’t exist.
From the seat of my observation chamber, I stared into the perfect void.
This is opposed to just a ‘void’ as a concept, which Taox seems to be referring to. Taox’s also trying to convince the sisters that the proto-Hive are “The natural prey of the universe,” which Aurash discovers to be untrue at the beginning of the Books of Sorrow, so some descriptive language to drive the point home isn’t unheard of.
Calus’ Leviathan was seemingly inspired by land-whales native to the Cabal homeworld:
I thought it would be cool if Emperor Calus was inspired to make the Leviathan from a creature native to his home planet, a huge land whale that would slide across the plains and devour anything in its path.
However, in Curse of Osiris, a bit of a 180 was pulled. As Calus himself says:
This Leviathan. This prison ship. I will remake it, as I have been remade. No longer will it represent a mythical beast from the dreams of worms. It will serve as an icon for my newfound gluttony.
The ship isn’t the “same species” as the Leviathan, given that the ship isn’t really ‘alive,’ but it was- at least originally- inspired by it, hence the similarity in the names.
It’s commonly assumed that the wish-dragons are/are very closely related to the Ahamkara, yes. This comes from the wish-dragons’ proximity to the Traveler during the war with the Harmony, as well as their ability to, well, grant wishes. There’s also the fact that the exotic perk of the Young Ahamkara’s Spine in Destiny 2 is called “Wish-Dragon Teeth.”