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Congrats. It's cool how affordable gaming laptops are starting to become. I just got one myself with specs as good as my desktop rig for barely over a grand.
1+2. If I'm not mistaken you should be able to run games at or above PS4 settings with those specs. By default I'd select 1080p with medium settings for modern games and adjust as you go.
3. It's the software for your hardware. So long as you stay up to date with Geforce Exp you've got nothing to worry about. I prefer picking my own settings over the ones that Nvidia recommends, but they're another good starting point for those unfamiliar.
4. A lot of the old tricks and programs are less important these days. Keeping drivers, antivirus, and security patches up to date are the most important bits. New laptops often come with plenty of bloatware you might want to uninstall, too (just be careful not to uninstall an important driver by accident).
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