iCloud files uploads like apps files works…

iCloud is not a storage service, it's basically a syncing and backup service. If you need off-site storage, I'd suggest getting a free Dropbox account and sync files to that. For music, you need to subscribe to iTunes Match in order to store music on the cloud. You can delete apps any time and later get them from the iTunes store for free (assuming you bought them earlier).

But the bottom line is, if you want to off-load files to save space on the iPad, icloud is not what you want.

iCloud does not have a service like the old iDisk. You can use Dropbox - it's a much better service than iDisk ever was. icloud does not provide generic storage like iDisk did.