It's a security related app, so the less unnecessary software the better, but that can be improved over time. If I do use AOSP would the "app" be a real app, o

It's a security related app, so the less unnecessary software the better, but that can be improved over time. If I do use AOSP would the "app" be a real app, or would it be a custom "launcher" that replaces the desktop and app navigation screens (are those two things different or is the launcher just an app)?