Do Apps restart after phone restart once "Force Stop" is enabled for them? Building the question on this What does the “Force stop” button mean? , If I restart the phone , do these Background Apps get started even when ForceStop is enabled?
Force stop is a one-off action, not a thing you enable or disable. Force-stopping an app doesn't prevent it restarting any time it would normally start: when you launch it from the apps menu, or through a share action, or automatically via an alarm, broadcast, or on start-up.

The question you link to talks about whether the button is clickable (enabled) or greyed-out (disabled). That's to say, it's about under what circumstances the Force stop button is available for you to click. Force-stopping an app just stops it once, when you click the button. The only long-term effect it has is that force-stopping an app might (in rare cases) corrupt its settings files, making it behave unpredictably in future.