My personal explanation is that Circe was behind the whole thing.
I would love to think that, but the idiotic scene with Lex that interrobamf reminded me of (now added to the top of the post) precludes that by showing that Ballesteros approached her, with a plan to "rule the world" zomg. He wouldn't need her help for the Swan thing, so that means the Cheetah business was all his idea; having Circe be the one to wrench the power away and give it to him makes it workable (though Psycho's involvement and that whole scene are still utterly baffling), but we're still left with Sebastian at the reins, which doesn't make sense (he doesn't have Circe's history with Diana or Minerva, so why involve the Cheetah at all, when he could just bargain with Circe for power straight up?).
It's too bad that Angelo only showed up in YJ after this.
Nah, that was a guy in a funny suit with a ranged energy weapon of some kind... not as bad as Pfeifer's take but still not Angelo.
That's debatable.
See my reply to scottyquick above. Marriage for love and long-term official coupling based on sexual attraction aren't common concepts period in human history, much less in religious ritual.