I do believe is all about context. Ideally, the final battle should be the culmination of your story, plot and themes alike, so if it makes more sense for your climax for other character to land the final blow, you should 100% go for it, but if it's variety for the sake of variety, then I'd say stick to what feels right.
I think this is a rather sparse trope, specially when you think final battles, but that's because usually the MC is the focus and carries the themes. I can think of some examples, though they land in the ''MC and friends'' category, somewhat: Gohan vs Cell (if you consider Goku to be the main character even by the end of Cell Saga, which I actually don't), which serves the purpose of passing the bat from Goku to his son; the final dunk by Kagami in Kuroko no Basket, though it comes from Kuroko's assistance and cements his place as the Shadow; Team 7 vs Kaguya, if you consider this the clímax and Naruto vs Sasuke to be more of an epilogue, showing that team work is cool and yay!
Those are not exact situations, but they all have narrative reasons to happen the way they do. It makes no sense for Kuroko to make the final points while it does for Sakuragi in Slam Dunk. Each character arc asks for something unique. Yours may as well.
It's not final battles exactly and not manga, but I'd like to mention Ultimate Spider Man, since it was all written by Bendis. I think he deals really nicely with variation and theme in battles. For example, through the 200 somethings issues, Peter Parker fought Norman Osborn and his legacy many times.
Their first fights, Peter always landed the final blow. When he faced Harry Osborn, turned Hobgoblin by his father, he refused to land the final blow, so SHIELD did for him, which spoke true to his character and thematically expanded on the tragedy of Harry. Then, when Osborn came back, Spidey vs Goblin was interrupted by his son, becoming Green Goblin vs Hobgoblin until Harry was dead and Norman surrendered, SHIELD landing it again, variations. It culminated in Death Of Spider Man, in which Peter had to land the final blow before dying, because themes. When Peter was reborn, some 40 issues after, Norman came back as well and by this time, Miles Morales was around, so he landed the final blow for the last Ultimate Green Goblin story, even though he's Peter's nemesis, to land the point home: Miles Morales is now Ultimate Spider Man.
It's all about what you want to say!!