Instead, you can go to settings 》battery scroll to the bottom and find "fast cable charging" turn it off. Note that you must not have the device plugged in to switch the setting. I hope this helps
No, it may auto update while you're not using it. My dad's note 4 auto updated from 5.1.1 to 6.0.1, so you may want to go to Setting, Software Update, and find Automatically check for updates. Make sure that it is not checked.
Re: Disable Turbo/Quick charge?
Although the Samsung chargers are only 9 volts (as to 12 on Motorola's charger) the phone still sees it as "turbo power connected"