Oooooooooooh, you're really good at this! I guess maybe Snape, he completely toyed with book 6 Harry after all, and book 6 Harry is already above avg. as far as fighting skills go. Moody... I'm guessing he was only a little bit ahead of Kingsley, seeing as Kingsley is the best, and Moody was the best, so he'd probably be around Bellatrix's level.
Oh, you meant for the battle to be staged with both of them in their conditions by Book 7, not just how good they were by the end of Book 7? Oh, then I'd agree with you.
Wait, what? What's the difference? 😕
Don't forget, though, even though Neville was a year older, both were given the same training by Harry, so Luna would've had the same amount of knowledge as Neville. (by the way, McGonagall was hit by surprise by Umbridge's goons, I think.)
But Neville improved faster than anyone except perhaps Hermione, he likely received more advanced stuff from Barty Crouch Jr. as a 4th year student than Luna did as a third year student, plus he had an extra year of DADA from Quirrell. Quirrell's classes may have been a bit of a joke, but I'm sure he taught them some stuff, as the book doesn't satate him to be completely worthless like Lockhart and Umbridge were. And he even went through one year of N.E.W.T. DADA with Snape, and Luna didn't.
About Quirrell and Karkaroff, I'd say Karkaroff would win. Even though we haven't seen much from either of them in the books, Karkaroff became the Headmaster of a school that excelled in the Dark Arts, indicating that he has extensive knowledge in that area. Wikipedia says that Quirrell was at best a mediocre wizard, but I haven't seen any evidence to support that. Quirrell was Defense Against the Dark Arts teacher, showing that he also had some knowledge about the Dark Arts, but Karkaroff was older and more experienced.
Karkaroff has knowledge, yes, seeing as he was once a Death Eater. However, having knowledge doesn't mean that he has skill. About Quirrell being only mediocre, it also says "though this could be a simple coverup so no one suspects his secret." Which seems accurate: After all, Quirrell's stuttering was a cover-up ("Who would suspect p-p-poor, st-stuttering professor Quirrell?"😉. Karkaroff is older than Snape, but Snape would beat him. Quirrell has performed magic without a wand, something we've only seen exceptional wizards do. He has done magic by snapping his fingers, and was about to perform a deadly curse using only his hands (when Harry touched his face to stop him). He broke into Gringotts and escaped from a high-security vault, which is supposed to be impossible. Also, he nearly had Harry off his broomstick even with Snape muttering his "silly-little counter curse". While Quirrell had a head-start (since he was already jinxking the broom by the time Snape started the counter-curse) and he may have practiced the curse before performing it to make sure nothing went wrong, but it's still impressive that he was able to nearly have Harry off his broom even with Snape trying to stop him. I'd say Quirrell kills Karkaroff, I think he's a lot stronger than people give him credit for, and no, I don't think Voldemort was increasing his powers, either. Voldemort was next to dead, he was pretty worthless on the back of Quirrell's head. Plus, in book 4, he says sometimes he possessed Snakes, but they soon died from being possessed by him, so if anything, Voldemort would have made Quirrell weaker rather than stronger.
Amelia Bones vs. Severus Snape?
Madam Maxime vs. Kingsley?