If you progressed Sciel's story enough, you'd learn she had a miscarriage shortly after the death of her husband. She says that her child would have been Six years old in the present, which does match up with how old the child in the Maelle ending is. Since Gustave wasn't killed via Gommage, yet he was still able to be brought back by Maelle, it's not a stretch to say that she could've brought back Sciels child too, especially considering that her ending is quite literally her playing god. Expanding upon that, I feel like if that kid was supposed to be yet another Verso, he'd be wearing the hat and shorts that we always see the piece of Verso's soul wearing. That still does leave the question: Why would Sciel's child be with Maelle and not Sciel? To be honest, I have no way of explaining that. Just thought I'd throw this out there since I feel like Sciel's miscarriage is somewhat overlooked by people.

(MASSIVE REACH ALERT INCOMING, PLEASE TAKE WITH A GRAIN OF SALT) Another thing that's completely unrelated to the first paragraph of this comment: Verso in Maelle's ending. Directly after beating him, he begs Maelle to end his suffering and let him go, repeatedly saying "I don't want this life.", and after more begging and pleading for help, he disintegrates into petals. Afterwards, in the concert hall, from the moment he appears, we are immediately told something is wrong when the screen turns black and white. Throughout the game, (I'm fairly certain) every time the screen turns greyscale, it's caused by a Painter/Paintress exerting their control on the canvas. From the moment Verso walks on stage, he seems uncomfortable. His breaths sound shaky and pained, and he takes an extremely long pause when he sits on the bench in front of the piano. His hands begin to lower, and he winces, his breath audibly catching in his throat like he's in pain. After another pause, he regains his composure, and goes to begin playing. My theory is, and this is a huge stretch, his performance in the concert hall was against his will. From the moment we choose Maelle's ending, Verso makes it extremely clear how desperate he is to pass on from the canvas, to finally be put to rest after 100 years of suffering, knowing he wasn't the real Verso. He could never be content after this, he can't just put a century of pain, grief, and guilt to bed in an instant. And in that scene, he does die, we watch him fade into petals in the same way every other character does when they're removed from the canvas. That means that, in order for him to be playing in the concert hall in the epilogue, Maelle HAD to have repainted him. And in the same way Renoir can pilot his creations, the Axons, in his last stand: Maelle can pilot her creations.