I need to swap out a number of pages without breaking incoming links (and without simply replacing the content on the existing page). Is there an easy way?
As far as I know, there is no way to swap page links like you’d like to.
What I would do, personally, is instead of swapping pages, swap the content on the pages. You could do this fairly easily by putting all of the changing content inside a wrapper HTML item. Put all of these wrappers on a new master page (so they don’t publish), then copy them over to the page when you want to swap the content.