There is no single answer to these questions. Different people prefer different workflows.
Here are a few thoughts, though
1. You can have as many or as few libraries as you like.
I am partial to small libraries and tend to follow the "one library per production" motto.
There can still be, and there are, several projects per library.
One of the things I do is reports on my son's football games ('football' as in the "beautiful game" that is actually played with the feet, not the other 'football' :-)).
I have one library per game instead of one per season, say.
For me, I would rather have a "New York 2013" library and a "New York 2019" library, but having a "New York" library with "2013" and "2019" events would work fine, if you prefer it that way.
2. Events are an organizational feature inside libraries. In the situation you describe, I think it would make sense, if you have a New York library, to organize the material in events as you describe, especially since we got library-wide smart collections, which allow us to easily find stuff even if we don't know in which event they are. This leads to a point about metadata (keywords, notes, dates, etc), which is one the key strengths of FCP X. If you take the time to organize and tag your content, you'll be rewarded later on (even in 2019, if you have to search for a specific shot you did in 2013).
On the other hand, it is also acceptable to have only one event per library, as some prefer; again, keyword and smart collections allow you view your content in any way you like, so you might as well not bother with events at all.
My heart is a bit divided on this one. For the football games, I have only one event, but in other cases I tend to keep using events as a way to organize content.
3. I don't know what "a bunch of things" actually are, so I can only offer this advice: don't delete something if you are unsure what is. If you like, tell us what you are talking about so we can perhaps see if it is necessary, or relevant, or what. That said, I fail to imagine what these things are. FCP X does not litter your drive with 'stuff'.