But what I want to know most is during that time did Iku and Yori go out another guy or girl?
I think that they didn't (they don't go in deep in this). Iku was working for Yano, but he had long given up on her, before the time jump (little by little, he realized that he just couldn't get in their way, due to many events, some small, and some big events (Yano's house was the siblings... love nest)).
Did their parents find out about their relationship?
The Mother caught them in bed, naked, during... well, you should know, even before this she suspected them and kept on spying them. This the gateway to the grand finale of the series.
Are they satisfied with being only brother and sister?
Did they still love each other when they seperate?
My japanese is kinda bad, but for what I gather, Yori was trying to get Iku pregnant, to prevent their parents from breaking them up. Before achieving so (they tried seriously) Yori suffers from cold feet, thinking something in the line that he was ruining young's Iku's life / future for the sake of his obsession. He then runs from home leaving Iku behind, never to return (but the story doesn't end here). Iku was not happy with this.
What do they tell each other after meeting up after such a long time?
Do they still love each other at the end?
They didn't agree to met each other, they bump by coincidence in a library in England, without speaking even a word they embrace each other in a romantic scene as soon as they recognize. I suppose that It's implied that... well, they never gave up on each other (this is also hinted in the extra chapters, where many little situations pre time skip are inspected, such as revealing that.Yori was Iku's first kiss due to a school play (to the dismiss of her mother)).
Do their chances of marrying each other increase as they are only half-siblings?
The manga doesn't really hint this, then I suppose that it doesn't.
Few more spoilers that might be interesting :
Yori's roommate was gay, and was jealous of Iku (who became proactive and quite skilled at sneaking in their room at night, as often as she could).
Tomoka doesn't end up in good terms with neither Iku nor Yori, due to pulling off a really nasty move on them. This causes Yori's resign that school.
The genius female exchange student, who was also enjoying getting in Iku's nerves, is Yori''s half sister as well (and gave it a shot with Yori as well). Looking at her behavior and character while knowing this, explains a lot.
Last edited by Black Hole at 3:10 am, Feb 24