[On Hold] Star Wars Preferences, Imagines, and Short Stories

Sorry, No, Not an Update

I'm really sorry for not updating. My life is hectic right now, and I need inspiration. My muse is not speaking right now. Anyhow...

I had a question. I was arguing with one of my friends about Star Wars related things, and then a question came up that that person WOULD NOT accept my answer.

Q: When Obi-Wan is on Mustafar, dueling his former apprentice, who is he fighting? And, if it's not Darth Vader, when does Anakin truly become Darth Vader? Also, does Vader redeem himself in Episode 6, after he saves Luke?

My A: He's dueling Anakin. Anakin truly becomes Darth Vader after Obi-Wan dismembers him and leaves him to die. Vader does redeem himself; why else would he become a Force ghost on Endor?
Why: I read both on starwars.com; Vader never really cared for Padmé as deeply as Anakin. I think he fully lets go of Anakin after he finds out Padmé's death. Vader becomes a Force ghost on Endor, but when he does, he's Anakin, not still Vader. In later versions of Episode 6, after the prequels were filmed, George Lucas (writer and director of Star Wars) replaced Sebastian Shaw with Hayden Christensen-who plays Anakin in the prequels.

My friend's A: He's dueling Darth Vader. Anakin became Vader after he was 'knighted' by Darth Sidious/Palpatine. Also, Vader was Vader from Corsucant on.
Why: Once he was named, he was named. He couldn't redeem himself; once a Sith, always a Sith.

I just want to know your answers, whom you agree with, and why. I'm just trying to see what the rest of the Star Wars fandom believes. Thank you!!