Where do Elsa's Powers Come From?

From the completely powerless King and Queen, a child is born with the power to control ice, create clothes and even turn snowmen to life. The question is... how?

And I know the answer.

If you listen to the songs taken out, in particular Spring Pageant, it's quite obvious that there's an ancient troll prophecy (and a director who's more than a little full of himself). The basics are that an ice queen will splinter the land, curse it with unending Winter and it'll only end with a sword sacrifice (sound familiar).

Now, you may just say that that doesn't really count, because they were taken out of the film, so we're going to go into the film now for more evidence.

When the trolls talk about Elsa's powers, it's asked how the heck she got them, and the rock trolls are vague as heck, saying that she could be born with them. Or cursed. The emphasis clearly shows that it is a curse, and the only hint of anything that could curse her is the prophecy.

Seriously guys, you just had to have a prophecy didn't you. You weren't
 happy enough being love experts, you now had to curse people.

But then, why did the prophecy occur then? It's never stated that it'd happen in a specific generation, just that it would happen. Sure it could just be chance.

Or it could be that dumb flower from Tangled.

Yes I'm talking to you. You're not getting out of this by glowing.

When the flower grew, the energy got transferred into the Earth by the witch singing the healing song. From there, it could have spread out, and, driven by the prophecy, been absorbed by the one person alive it could apply to.

Elsa.

With the energy absorbed through a different way, being attracted by the prophecy instead of the flower, it would have caused her to develop different gifts. However, the inherent healing would be there, but suppressed by the prophecy's power to make her into an ice queen, explaining how she could make Olaf and Marshmallow. And when the prophecy was weakened, the power of the sun could take more power, making it possible for her to warm Arendelle and bring all of the flowers back to life (because lets be honest here, those flowers were not surviving otherwise). But she still kept her ice powers, due to the chaotic nature of the prophecy attached to them.

I still don't know where the clothes design part came from though.