Re: Sephiroth - Do I think that fighting Sephiroth is tradition? Yes. Am I bothered he isn't in the game? No, and to be honest, I WANTED TO FIGHT ARDYN!

You can easily play that the Daemons are Darkness, and whatnot. In the chance that they make DLC boss fights, they'll sure as hell sure Sephiroth to promote FF7's remake.
Re: FINAL FANTASY - Am I bummed that Squall and the gang aren't in the game? Yes. But after watching the trailers and seeing the role every characters has in the overall plot, I honest to heart think that adding the gang would have been too much. The same way they weren't introduced in BBS because they would have been too much, I think they would have been too much here as well. Do I think there's a chance for Radiant Garden to be a DLC world? There is, but we would have to see how much work that would be for the team to dev.
Re: FFVIII - (Daily reminder that I need to play this game) I don't think FF8 is THE most hated FF game. I think that would be FFXIII. Remember that after "Corridor Simulation XIII" was released, everyone was eyeing Versus XIII as the next true FF game, and it's the reason as to why people hyped that project as hell, and ended up very disappointed with the development hell, rebanding and the end product we got as FFXV. And to the best of my knowledge, FF8's final dungeon is deemed one of the best of the series, as well as its theme, and its villain.