Follow the instructions as they're presented and you'll be fine

Installing it will make rooting easier, but afik root is not required (though you will be accessing the device at the recovery/bootloader level, something with far more control than root)

Yes, pay attention, follow the instructions and you'll be fine though

Respect your privacy, allow you to sandbox apps which want to spy

Everything should work because of the sandbox function, the same cannot be said for most other custom ROMs unless the Google apps have been installed.