What I said was really simple. The Darth Vader we know and love today is basically Kane Starkiller and General Vader combined into one character. Kane was a rogue Jedi cyborg and Annikin Starkiller’s father (who became Luke). Darth Vader in the original drafts was simply a general for the empire. The final incarnation of Darth Vader is second in command of the emperor, a Sith lord who broke away from the Jedi, a cyborg, and Luke Skywalker’s father.

So yes, from a certain point of view, Vader was always gonna be Luke’s father. Or at least, there was always an element of “rogue Jedi cyborg is the protagonists dad”.

I’m assuming when Lucas said it was about Annikin and his kids, he probably either misspoke, mixed up the characters, or he said that for convenience because he didn’t want to have to go on and explain who Kane was.