Magic seems to have been around for a few thousand years in Zeal, atleast long enough to use up the Sun Stone and most of the world's Dreamstone or something, which I don't think can be done in a single person's lifetime. Zeal is too elaborate and powerful to be the work of one generation. The way the people of Zeal act, most if not all of them were born into high magical society and don't know any better.
I don't really think so. The whole Earthbound thing seems recent. I mean, Schala and Janus used to love their mother. But Schala, as also one of her reasons, doesn't like her now because Zeal does not treat the Earthbound ones as humans.
And what do the Earthbound ones have different to the enlightened ones? They do not have magic abilities.
A person like Zeal, I would not expect any lesser of her than to create Zeal in a matter of years. When you have such powerful people backing her up like the Guru's, anything can be accomplished.
Also, you can't really base the Sun stone on much. It may take a hell of a long time to charge, but that doesn't mean it can power something for thousands of years. I mean, it only hard enough energy in it to cerate the Wonder shot, and the rest of the stone was used in the Sun specs.
Also, since they knew about elements and had elemental weapons, I wouldn't think past them that they had very simple abilities with elements, but nether the less, once Zeal established magic or found a way to tap into it and teach others, then the split between Enlightened and Earthbound occured. Though later, I only think then did the Earthbound ones get condemed for not being able to use magic. By lowering them, it would have been a perfect excuse to use them as labor.