I would hate the Adv CoO + CoC thing because Luffy already has Adv CoO, it’s called Future Sight. Don’t want another asspull “You can coat yourself in CoC?” Moment.
Luffy couldn't be anymore clear that his attacks was still classified his aCoA attacks against his final moments with Kaido.
CoC coating simply made his aCoA greater.
Shanks being able to infuse his CoC with his attack is already canon. And now being the only Emperor to infuse it with his CoO makes up him being DF-less.