Ideally, common sense and reasonability should prevail on situations like these. Yes, flight attendants should stop with the loud conversations and noise in the galley on overnight flights. But, on the other side of the coin, passengers should not expect complete and total silence either. For that, they should bring the noise cancelling headphones. And definitely chose a seat not near the galley to help avoid this.

I do think if a passenger or flight attendant is being too loud, politely asking for lower voices would be fine.

At the end of the day, a respectful dialogue could allow the passenger/FA to agree on an acceptable threshold. Would expect that most people are reasonable when it comes to these things.

When it comes to in general etiquette, the same standards should apply. On flights where I don't plan to sleep (i.e. domestic, even transcon mostly), I'll likely have the window shade open for the entire flight. But, if the passenger next to me asks me or if they're trying to sleep, even though I'd rather not, I'd usually close it. On long haul international ,regardless of time of departure, I'll typically close the window after takeoff.

Common sense and basic manners go a long way in these types of things