Video editing work? ... wouldn't take long at all to eat up 300GB of space with a video project.
(and as a project tied to an editing program, it'll show up as "other" rather than in the "Movies" category on that graph.)
No to both. At least Apple didn't design it to be able to do either. That's not to say some industrious 3rd party developer hasn't come up with a way to do one or both of those. But it would be what is considered a "hack" in the vernacular of the kids. . (Technically, that's the wrong term, but it's what they'd use.)
Yes, You're not really shutting it OFF... and some apps are still able to perform some tasks while asleep... perhaps there's some app that you recently acquired, or that was recently updated and that new app (or updated version) is what is using battery while asleep...
Or perhaps you may have changed a setting for push alerts or something similar?
I gathered he knew that ... I think he was asking if, after installing iOS7, he can then "restore" the phone from his last backup and get all the "stuff" back that he had to delete in order to do the install.
Well... you can certainly do an immediate "Restore" of the phone after installing the new OS, and it SHOULD give you the option after that to restore from a backup (but I'm not sure if it will... it's possible that it won't restore from an iOS6 backup.)
The servers/services Apple is using are swamped right now ... either keep trying, eventually it'll work... or just wait until tomorrow... this happens every time they release a major revision to thier OS (and will happen again when Mavericks is released.)