Only after establishing the authority relevant to each cohort and intended use. Holding the files or publishing a collective work does not by itself establish ownership of every contribution: US copyright law distinguishes these interests. US Copyright Office — Title 17, Chapter 2: Copyright Ownership and Transfer
Build cohorts using contract version, source, acquisition period and modality. An article can have separately sourced photographs, charts and quotations; treat those components explicitly. For each cohort retain the relevant agreement, rights interpretation, exclusions and accountable reviewer. Use “documented for proposed use”, “needs review” and “excluded” as working states, with final legal decisions made by counsel.
Do not extrapolate one favourable freelance agreement to thousands of unrelated works. Test a representative sample to identify the work required, then determine what population-level checks are necessary before granting warranties. For book content, Authors Guild model clauses illustrate why author approval and specific AI permissions may need negotiation; they are proposals, not terms automatically present in existing contracts. Authors Guild — AI-Related Model Publishing Contract Clauses
The practical outcome may be a smaller, defensible corpus. A rights-limited pilot can be commercially useful even when an archive-wide licence is premature.