Roughly 35-45 Hours the first time. If you are doing Hero mode it is closer to 25(if you are really fast)-35. But the average time is really close to 40 hours.
No, it is not the last. There would be a new (Not a remake) legend of zelda game for the 3DS, and possibly the Wii U
Skyward Sword will probably be the last Zelda game for the Wii because this year the Wii is supposed to be replaced with the Wii U. The next Zelda game is supposed to be for the 3DS, followed by a game for the Wii U, but not a lot is known about those games yet.
I am not sure which you are referring to because there are many. There are side quests and individual ones they appear at night.
Sky Keep
No? In almost all of the Zelda games Link in the game is a different link than the others, like how Demise states that the Hero and himself and the Goddess will be reincarnated, the Link from OOT is the same from Majoras mask, but after that link dies he is reborn many years later as Link from Twilight Princess. Skyward Sword, in accordance to the Zelda timeline, is actually the first of all the games so far. It will not end, it probably won't ever end unless Nintendo stopes making money... Which probably won't happen soon.
**SPOILER**City in the sky is also a dungeon level. Go to the shop in the city, (its located a little ways passed where the pool of water is) talk to the Oocoo. This will make the game continue on. A scene where a huge bird flies into the city should occur. Your goal is to kill it.
The duration of When the Last Sword Is Drawn is 2.28 hours.
You only have it in the twilight world so whenever you are in the twilight world you have the light sword.
once you get it...you keep it. its bean like that for all the Zelda games except for ocarine of time and majora's mask
You have to do an excruciatingly long trading sequence, so I'd look it up on Zelda Dungeon if I were you.
The Sword and Shield dungeon is located in Subrosia. You need to enter Subrosia from the portal in the Temple Remains to get there.
Most likely you either put the disc in around the wrong way or you need to update your Wii firmware. In the latter case, just update it. It doesn't need an Internet connection. I had to update for The Legend of Zelda: Skyward Sword last week.The region on the game has to match the regional version of your Wii, but unless you buy games from shopping websites this isn't an issue.