Don't know if this will help at all.
I have had a lot of the issues listed here a few times when trying to update the OS on my iPhone4.
Usually, if you have installed an updated version of iTunes just before doing the update, many anti-virus software programs have not been updated to work with the newer version.
Because of this, the anti-virus software may cause an issue with iTunes when its trying to complete the OS update ans restore process.
I shut down iTunes, then I shut down my anti-virus software completely, including the firewall. Then I went back to iTunes, and completed the install with no problems.
The apps, photos, music, and settings took a while, but they came back.
Hope this helps...