I'd like to create paragraphs (even entire sections of pages) that could be used in multiple sections of the site, e.g., a "Legal Disclaimer" section. The thought being when the Legal Disclaimer changed at the source, it would change everywhere. This I believe is the point of the reference component.
When I drop a reference component on the page, I can browse through other pages on my site and select a parsys just fine. I'm confused as to how to add paragraph to the content finder under the "Paragraphs" tab so that (presumably) I could just drag it to any page I wish. Are these pages or literally parasys (if the latter, how do you add them). I don't see any examples under the Geometrixx either.
If i understand your requirement correctly boilerplates  might be fit for your case.
The Paragraphs tab in content finder helps to filter and preview paragraph for the context path. Ex:- Type in the page path "/content/geometrixx/en" and click on search icon & it display all the paragraph. To verify add a text component to geometrixx en page and in cf it will get dispayed. You can drag and drop to an reference component.