Finder not searching files in ~/Library and /Library
You have to include "System Files" in your criteria to search places like the user Library.



To do so, open a search window in Finder cmdF, click on "Kind" and select "Other" and scroll down to "System Files".  Tick the box under "In Menu" for easier access in the future by including it in the search menu.
(You can also specify hidden files here, with the "File invisible" attribute)




You can also save those search criteria and add them to the Finder sidebar for quick access.



If the above does not yield the desired results, a rebuild of the Spotlight index might be required.