You'll likely need more schools to handle smaller class sizes or to expand existing schools. If the former, then you'd definitely need additional counselors and librarians since a new school would need its own support services. If the latter, then you only need additional counselors and librarians if the expansion to the school also brings in additional students and doesn't just spread the existing students across more rooms. On the other hand, you may need to expand the library to accommodate more classes needing access to it simultaneously. I know my high school had two libraries largely for that reason (also because it was a poorly designed building, but the space was well utilized for social studies and English courses).