that doesn't matter, he was left to rot for just as long as the other animatronics
there was nothing changed about freddy's actual mechanics. it was 100% cosmetic changes, otherwise henry would've found the bodies inside the animatronics
advanced doesn't automatically mean stronger, a nerf gun is more technologically advanced than a steel club but you'd never guess which one is stronger
a human head sure, but not half of a child's entire body. compared to michael (assuming he's the average american's height, 5'9") fredbear should be nearly 9 feet tall, making him the tallest animatronic in the series excluding security breach
wouldn't a better battery system mean more of the budget goes to the battery, and therefore less goes to the durability? regardless we've reached the depths of conjecture at this point