Vader should have it. Malgus by this point hasn't done anything that Vader can't replicate, or hasn't surpassed already. If this was Malgus after killing Eleena Daru, or SWTOR Malgus, I could see an argument for him winning, but not for Malgus concurrent with the Sacking of Coruscant.
Grand Inquisitor or clears. If I recall correctly, the novelization and the script both indicate that Luke was giving Vader legitimate trouble in their duel on Bespin, I don't see any of the Inquisitors being able to do that except for maybe TGI.
Bane. Canon Force users generally aren't as strong as Legends Force users, and Ahsoka lost to a version of Vader inferior to Legends counterpart. I don't see Ahsoka beating Bane because of that. Drallig should put up a decent fight though.
I haven't played GoW 3, tbh. If the Chimera was able to, in universe, give Kratos a decent fight though, then I'd say the Chimera wins by virtue of contending with a being that would slaughter Geralt (Kratos). If the Chimera was easily slain by Kratos though then it's kinda hard for me to gauge it since I've never played the game.
Palpatine slaughters. Dooku is the only one that MIGHT not get blitzed right out the gate.
There's a rather significant difference between what you think said and what I actually said.
The reason I said that he might not blitz is due to how he fights. He could have blitzed Maul and Savage, but he didn't, he toyed with them. I've no reason to suspect that Sidious is behaving any differently here, and so, if Sidious isn't going all out, and chooses not to blitz, then he by definition, does not blitz, and thus Dooku does not get blitzed.