Could a Hermes built with a seaplane-oriented layout later become an amphibious assault ship?
Short answerPossibly, but only if treaty accounting placed her outside carrier tonnage; otherwise the Royal Navy would have retained her in the carrier role.
NotesThe conversion was technically plausible. The limiting question is whether the Washington system counted the ship against scarce carrier tonnage or allowed it to sit under auxiliary or specialist categories. A carrier-tonnage charge would make continued aviation use much more valuable.