I placed the war after the civil war in America myself, because that was when slavery(Not world wide of course) ended in my head. Just call me a selfish American :P That way we would have E-male and Intronet, along with all the gizmos needed to enslave the magicals electronically.

As for the precautions. . .Alexi is a light sleeper, he would hear Erik moving his chains around that much in his sleep, and while Alexi is not there, I would say that the magical chains would recognize such an attempt and, not being the will of the one that sealed them, would circumvent his actions. There can even be a seal on them that knocks him out when he gets too violent. Humans may not be naturally magical, however they have learned to use it over the years. So, in short, his magical chains will not let him kill himself. Magic for the win!