Launchers and features analysis

I am using stock moto launcher on my device. And, the night drain is about 6%. So, I decided to use Nova launcher. Installed Nova launcher, and after that night drain is reduced to 3%. I need to know more about launchers. 1. Launcher's ram usage: Do both launcher's run same protocol/processes (eg: notification dots like processes). 2. Device running in Nova launcher, and started some apps. Then, I switched launcher to stock(uninstalled nova). Those, apps still remained in RAM. Why the apps not get reset while switching/ not removed from RAM. 3. Some widget features got reduced. For example, google widget. It always contain text "Say Ok Google" in stock launcher. But, it is not available in Nova or pixel launcher. Why?