I believe that's true, yes. Though the concepts of angelic and demonic heritage are not, as Corvus Belli points out. I'm relatively sure those words were coined by writers working for WotC, though it could have been TSR.
Those words existed before D&D and have been in usage for a very long time. Tolkien, for example.
Angelic levels such as 'Hosts" and "Legions", while non-Biblical, come from Rabbinical works predating modern Copyright Law (as do words such as "elf", "dwarf", "giant", "kobold" and "orc", even if the modern forms don't mean the same as the original usages).
TSR had to change "hobbit" and "ent" due to litigation from the Tolkien estate (to "halfling"and "treent"). And the first couple of editions of the Deities & Demigods guidebook included sections for the Cthulhu Mythos & Michael Moorcock's Melnibonéan Mythos which were removed from later editions due to threat of legal action. (That's technically incorrect- as in most things, the situation was more complicated, but this is a case where a over-simplification is justified. And it amounts to pretty much the same result.)