Grandia III Spoilers Questions Unanswered?

I am a great fan of Grandia! I completed all 3 in the series and I'm a first time poster in these forums.
Major story spoiler alert if you read on and haven't played (you've been warned)
My first question is on the main map, Why is there a Clan Lake and an area that mentions Sky Captain Schmidt was made famous for airplane races? There is no mini-game with riding the airplane so the loop/barrel roll was cool but unnecessary. No side-quest at Clan Lake either.
(Both areas are not land-able)
What happened to Kornell? I thought he was a foe that was going to help you out some way in the end, after he realized the error of his ways with Emelious trying to kill him and Violet when they were going to kill Yoat Guardian. You see him in Surmania one last time in a FMV sequence with Xorn's revival attempt.
Who is Grau? (Emelious right-hand man) that betrays him in the end when Xorn is reborn. (Was he the mystery man in the FMV sequence that displays when you observe Emelious' diary. Talking to Emelious younger self and became angry when Emelious mentions he doesn't want to be a communicator?)
Bianca makes an appearance in Baccula and creates a "Supermarket" but the characters never see her again after Sabatar Harbor casino scam.
S.C. Schmidt plane goes down in flames when he escorts the party to Sumaria does he "really" die, and no-one including Yuki mentions of him again? (Considering after helping Yuki make a plane and all the help he lend-ed the party as a NPC)
Just a few more questions. (thanks for being patient if you are a Grandia fan and still reading this)
Why do you hear talk of Alonso and Miranda coming to Sabatar harbor from sailors after Sumaria rises into the sky but can never see them again? (Until ending snapshots)

Last question... I completed the PS2 version.
I'm aware Grandia originally was on the
Sega DC, did it more content on it and is it possible they removed some stuff for the PS2 version? I hope someone reads this and can answer my questions, as I mentioned I'm a fan of the series.
Grandia 2 I enjoyed the least. This game however I'm curious about a few things they didn't explain.

Thanks Saevus for replying, I must sound like a total nerd for expecting an actual answer to the poorly unfinished plot/loose ends of an otherwise great story.
It leaves me with mixed feelings as well; because of it, I feel Grandia only has a one-time play through because no reply value to explore/acquire anything. Too bad they wouldn't create a great Grandia game with side quests like the original Grandia.
I'm going to stick with Tales & Final Fantasy series of games in future, it lacks the battle uniqueness of Grandia, but at least it's a well thought through story with no unfinished plots or game play elements that leaves players with a feeling of undesirable fulfillment.