For KH2 Sephiroth youre supposed to open the left handed Fitmotion to make him look right THEN you pose him. VII Sephy, I have no idea. It looks fine to me in-game.
Whoa that's pretty epic, but that's the wrong blade for AC Cloud, but nvm. You don't have to fix it.
Hmm...for the VII Sephy it looks fine to me and for KH Sephy, did you use the left handed motion from DivineOverlord's PSA? It's the only way to view him as normal
As for Dissdia Cloud, it's rig probably needs some improvments.