Squall wants to take over the Yggdrassil system which governs all IS. So she plans to backstab the forestfolk and Tabane after gaining their trust and playing both the adventurers and the forest for chumps.
Tabane can live permanently in the system. But Houki has the "right" to inherit the system as programmed by Tabane. Because she knows how Houki's life has been hell due to her. She believes that the only person worthy of inheriting the system is Houki who will plunge the world into the final formatting
Not really. Most people just don't find anything cool about Ichika right now. But the cool points about him are just scenes that don't come out due to people afraid of making him cliche. He has the makings of an epic shonen hero but everyone can't see it because the shonen hero type Ichika would become is a hybrid of hot blooded young man and shoujo male lead.