[ngng]

Scientifically speaking there is no magic, that is what I meant.
Without the English patch for Ep8, I can only take a guess according to my understanding if you don't mind.
If you think about it, Yasu's birth was already strange in itself (being Kinzo's daughter and granddaughter at the same time). My guess is Kanon does not exist in the real story, Ep7 explained that Yasu has many personality, but I think she does not disguise herself as Kanon or Shannon in the real story which involved the real Battler in ep8. Rather her hidden feelings inside her head develop those personalities, but no one know or else she would have end up in the hospital. I think she conceals those personality so that only she knows about them instead of admitting them openly like Maria lest she risk losing her job.
Yasu or Yasuda is only human body and she looks like Lion, everyone would knows her as either Yasuda or Shannon, Kanon the boy does not exist as a human body.

Why she develop Kanon might be due to the complicated feeling and immature feeling she might have toward Jessica when they were young and accumulated stress and belief that Battler does not come back due to him not writing her a letter as explained in ep7 in a magical way.

Dating George is also a replacement for Battler, but Yasu loves Battler the most so when Battler finally comes back in 1986, she decides to get back to him by testing him with the epitaph I think and the gold was revealed but Kyrie started the killing spree due to her greed and almost everyone dies except the two of them. They both did not want the gold (different from Kinzo and Beatrice I) so after the massacre, they both decided to commit suicide, but unfortunately, Battler survived so we have the 3-6 games as fantasy novel written by the surviving Battler, the 1-2 games are stories in the wine bottles (somewhat similar to Keichi's message in Onikakushi) written either by Yasu or both of them before suicide (remember they both loved mystery novels) as a diversion to the true story. Maybe Yasu did not want outsiders to dig in and investigate the many dirty stories about the Ushiromiya family because she and Battler are both Ushiromiya and related somewhat, or they might want to compete who wrote a better story before dying.

That is my speculation before the English patch comes out. Ep7 gives more extra hints and history and confirms Yasu=Shannon=Kanon all along, but ep1-7 are probably fantasy or parallel worlds, as much as I like the parallel world theory, the current world in which we exist now is more important, I probably would not dismiss them because they give background info and motives to the crimes, but don't take them as different kakera like in Higurashi because Ep8 told us that the story already has definite ending that makes sense and wrap up all episodes as a whole so ep1-7 does not have any influence on the real event that already happened to the real Battler (Hachijo Toya in 1998). It only give us clue and insight to uncover the real story.

So in conclusion, Battler and Yasu are victims of a sad tragic love story that does not have a happy ending much less a perfect ending (a perfect ending would be either they both die or survive) Remember, this is my speculation after knowing about that one specific ending in ep8, I cannot read Japanese so I can only wait for the English patch. If you rearrange all episodes in the right order from the wine bottle 1-2, then comes tells what really happen in real world of from 1986 to 1998 in ep8 and then says Battler wrote the story from ep3-6 then that would make perfect sense. I think ep7 should stand alone as Beatrice's and Yasu's story instead of combining it with the fantasy novels Battler wrote minus the magical aspect and then we would get the most linear and understandable novel of all time.

One last thing, it's ironic that Battler who inherited Kinzo's blood the most would fall in love with Kinzo and Beatrice II's daughter Yasu who though only possessed 1/4 Italian Blood still somewhat looks like young Beatrice when she let loose her long golden hair (watch Umineko Graphic Motion Vol.8 that has spoiler for Ep7). So as you call it "fate" let Kinzo ties himself with Beatrice and fall in love with her 3 times, 2 times directly and 1 time indirectly through the grandson who inherit his blood the thickest (Battler looks like young Kinzo except the hair). A sweet story with a sad ending.