I am sure these names have long histories attached to them, but some of them seem pretty badly conceived.
Jubilee means celebration, change the last 'e' to an 'x' and it is a faceless demon lord?
Orc is one of the most common people in virtually all D&D worlds so "Orc-us" seems an odd name for a demonlord with no relation to them. It would be like having the name "Elwyn" on a celestial lord that had nothing to do with elves.
And Demogorgon? As in "Demon Gorgon". The combination of demon and the general greek word for monster. That one just seems lazy.
I get that they are trying to reach out to old school fans, but... man.. I think I would rename these guys if I were going to use them in a campaign. The others are fine, but those three are in desperate need of a rename. Maybe include a second name as an AKA. Surely their names aren't the same in all languages.