This final one isn’t one you will be able to do without either development or Google Tag Manager in place.
Along with goals, it can be a vital way of understanding what users are doing ‘on-page’ by that I mean out of the box you get a view of what pages users are loading and also how they flow between pages, what is harder to gauge is how they interact with those pages. Do they click buttons or engagement with rich content for example? That is when you would want an on-click event.
While event tracking has been around for a while, it is certainly becoming more relevant to GA moving forward. Googles latest version of analytics GA4 uses event tracking as a core measurement method, you can read more about that here.