How likely is it that the Dominion battlecruisers last into World War II?
Short answerThe specific old ships may be replaced, but Dominion capital-ship fleets are more likely to persist because the historical Washington treaty is harder to impose.
NotesThe old battlecruisers need not remain in service unchanged until World War II because Britain or the Dominions could continue building and pass newer second-line ships outward. More importantly, multiple governments with bases, crews, and capital ships would resist simply abandoning that investment. Australia historically surrendered a single battlecruiser, but securing equivalent concessions from several invested Dominion governments would be more difficult. If the United States has less influence because it entered the war late or not at all, the historical Washington Naval Treaty may never take its familiar form.