I was looking through the EQ lore and there are 2 different sides of the lore which one says, Firiona is daughter of Tearis Thex while the other side of the story says she's daughter of Galeth Veredith and Tearis' wife. Which one is more accurate?
It's more complicated than that actually. Galeth Veredith was a spirit that inhabited the Plane of Growth. He inhabited the body of a slain High Elf, and then in that body seduced/fell in love with (conflicting versions of the story) the queen (Tearis Thex's wife) and impregnated her. This happened either before or after (again conflicting versions of the story) she was locked away in a tower. Regardless, she died in childbirth and Tearis Thex believed Firiona Vie was his daughter until it was revealed much later she wasn't. At least not biologically. TL;DR she's the daughter of a random High Elf (his name might have been mentioned but I don't remember off hand) who was possessed by Galeth Veredith.