No. Replacing the battery will not wipe the phone. Make sure the phone is off before you disconnect the battery though!
factory reset it or restore it
if you have all your media on your itunes and other files backed up in itunes (backs up on sync by default) then you shouldn't lose anything
You erase everything from your iPod by connecting it to iTunes and click on iPod and click on restart.
you go to your history and erase everything
the same way with all of the other iphones
restore it on itunes
http://www.webtree.ca/windowsxp/repair_xp.htm
You cannot remove everything off your profile.
All you have todo is attach the iPhone to your computer insure iTunes is open and then select restore to factory settings options, which will reset the handset and erase ALL previous data.
yes it will
Actually, It doesnt. 'Cause its the purpose of backing up the data. After the update, Your iphone will restore then it will put back your old data.
Yes there are many Apps out there ex: Find My iPhone and also if you have iCloud account setup you can remotely erase the data from lost/stolen iPhones