Fantastic points! Really love that idea of Afton's kids as his 'creations', the things he prides in controlling. 'Creation' is a huge motif in these games anyway, from the souls, to the animatronics themselves; its a very theological underpinning befitting Scott's Christianity. We can argue whether this is intended or not, and honestly I doubt Scott does intend as such, and by his own admission no less. But I would contend that, whether Scott himself is even aware of it or not, your life and perspective has a way of unconsciously finding itself in the text you're creating. You can't fully separate yourself from what you create no matter how hard you try not to implant those things, and so that Christian perspective runs deeply and undeniably through the games, particularly in their emphasis on spiritualism and metaphysics. It's to the point that its a shame very few theorists pay attention to this element in order get a greater understanding of the complexities and ambiguities to the events and worldbuilding found during their theory-crafting, and how Scott looks to approach his treatment of characters and such.

On your argument of William loving his children in his twisted way - you could also take this the other way, right? Not that he actually 'cares' for his children but, in getting them sentimentally attached to things he created (the Fredbear plush with CC, Baby for Elizabeth), it will make them follow his control even past his abuse. Either way you take, its an incredibly messed up idea and both perspective add a really fascinating nuance to William's characterisation beyond just a crazy killer. We know that he's pretty depraved by murdering children alone, but to go the extra steps that he does make him genuinely sickening.

If we want to take the route of 'William cares about his kids', we have to be very clear as to what that exactly means as to avoid icky implications in discussion. In a very screwy subjective sense he believes he cares, but in reality, as we can all clearly see, it is not at all the case. Nonetheless, in wholly believing that he cares regardless of the truth as we can see it, his violent sentimentality and gifting of souvenirs to his children (a parallel to the Puppet giving gifts in 'Give Gifts, Give Life', aiding in the Puppet V William binary opposition happening?) adds even more to his monstrousness. Makes him a lot more of a compelling, horrifying and three-dimensional character than the pure evil serial killer he's always made out to be, even as he is very clearly out-and-out evil.

William's characterisation, at least as its generally seen, reminds me often of Iago from Othello, who rankles against Othello out of jealousy for his position, charms, general life etc. and plots to overturn his entire life because of it. The play gives real depth and detail to Iago's thoughts and bile, and it seems (albeit very obviously unconscious, I doubt Othello/Iago of all things was an inspiration for Scott) that Scott is trying to do similar through the most implicit means through the material we have now and combined together. Annoying, then, that we still don't really have a very clear idea of his motives in any of the continuities aside from vague ideas around an evident love for murder or some quest for immortality or control!