Will be doing a back up of an iPhone 4 still on iOS 6, then a wipe and restore from back up.
Will the complete contents of the iPhone be saved and restored, to include texts and voicemails?
I plan to follow these instructions from Lifehacker. Are they current and workable?
What to Do If You've Forgotten Your iPhone's Passcode
Restoring your iPhone is a surefire way to wipe out the passcode or password you can't remember, but performing a normal restore won't work as your passcode will prevent it. (Arrgh!) Fortunately, this is easy to override. Just follow these steps:
Even when your iPhone is locked up, you can still sync it with your computer. Do that first so all your data is backed up in iTunes. If you're using iCloud, you might want to switch it over to your computer for now just to be sure your information is safe.
Put your iPhone into DFU mode. To do this, reboot your iPhone by holding down the power and home buttons simultaneously for about 10 seconds. When you see the Apple logo, let go of the power button but continue holding down the home button. Soon you will see an image displaying a USB cable, the iTunes icon, and a message that says "Connect to iTunes."
Assuming you still have your iPhone connected to your computer with iTunes open, you'll also see a message telling you iTunes has detected an iPhone in recovery mode and needs to restore. Now you can click the Restore button in iTunes and then wait for iOS to download and install on your iPhone.
Sync your iPhone with iTunes to restore all your data and you'll have it back to normal with no password!