HP & The Half-Blood Prince establishes quite firmly that he uses Legilimency to constantly read the mind of whoever he's fighting. That's already one major advantage; Lincoln won't be able to do a thing without Snape reading and countering him the way he did with Harry.
Add to this the fact that he's qualified to teach sixth-year Defense Against the Dark Arts, meaning he's easily one of the more well-versed teachers in Hogwarts. You don't get to teach that position unless you're exceptionally skilled in spellcasting. Or a talentless hack like Gilderoy Lockhart who managed to talk your way in thanks to your own wholly undeserved reputation. He should at the very least know every spell that Harry and Hermione know, as well as numerous others.
And morals off means he won't have any problem using more dangerous spells and curses right off the bat, which is another severe advantage. A good few of these spells will kill or cripple Lincoln with a single use.