You can back your phone up but you won't be able to use that backup. Like I mentioned in the previous thread your backup will still have the restrictions code so you would be in the same boat. You can sync your pictures to your computer. Your texts will be in the backup so until you figure out your code you won't be able to see them. Assuming you're using the iPhone messaging app.
Oh and your music I assume is already in your iTunes (only way you could get none iTunes purchases on your iPhone). iTunes purchases can be redownloaded for free by going in to iTunes, signing in to your account (Apple ID) and clicking on Purchases. Same for apps and anything else you purchased/downloaded from iTunes.