Hi,
The three policies are not for the same setting. But they do have a close connection.
Turn off display: You can specify how long your PC is inactive before all your connected displays turn off. When your display turns off, you would just need to move the mouse, touch the touchpad or touchscreen, click a mouse or touchpad button, or press a key for the display to turn back on. Password not needed .
Screen savertimeout : A screen saver is a moving picture or pattern that displays on the screen(s) of your PC after you have not been active on the PC for specified period of time to wait. It was used to force the computer screen to lock itself after the inactivity time you set . To login ,it requires password or not depends on the Password protect screensaver is Disabled or enabled.
Interactive logon: Machine inactivity limit.(close to screen saver timeout setting)If the amount of inactive time exceeds the inactivity limit set by this policy, then the user’s session locks by invoking the screen saver (screen saver should be active on the destination machine).
For your questions: what will be the result of all these 3 group policy settings
The device locks not only when inactive time exceeds the inactivity limit, but also when the screensaver activates or when the display turns off because of power settings.
The password is needed for both the 3 situations mentioned above.
Best Regards,