Sorry for the slow reply to this! So slow that you've updated already! I hasten away to read. :)

But just as I leave: I think the importance of a Pevensie marriage is greatly over-estimated by fandom (partly due to too much attention to how the British monarchy worked in the twentieth century). It's a basic requirement for monarchs (or any leader) to sort out the succession, but it doesn't have to be through parenthood; orderly successions have achieved via remoter connections, by adoption, by election. Examples from history on request. :)