Unless you "Transferred Purchases" to your iTunes or made a backup of your iPod, there is ABSOLUTELY no way to.
Yes, restoring your iPod will clear all contents on your iPod.
going back to default settings
Yes, but you can sync them back
You need to back up your iPod on your computer before you restore it.
No, restoring an iDevice wipes everything
Restoring an Apple Device takes it back to factory settings so yes, it wipes the device's previous data. Best to back it up before restoring
you can't, but there is this program called iPod rip. but i doubt it works with the new firmwares apple uses on their iPods.
You back it up on itunes, then reload it again
Of course...by restoring the ipod.
Yes, restoring your iPod will take off the jailbreak, and you will have to jailbreak it again.
What you are doing is 'syncing', and every time you sync your iPod, it will back it up. If you do not want to back up your iPod, highlight the music from your library that you want to put on the iPod and just drag it onto the iPod Touch menu.