The Other Kellen and the War Magicians will appear in the trilogy after this (working title: "The Glories of the Autumn"), since it is about the Second Endarkened War (so you get your wish!).

But you don't have as long to wait for a (partial) answer to your questions: there will be Bearwards and Merfolk a-plenty in "Blade of Empire", as well as a look beyond the Bazrahil Mountains, and the landscape as it was before the Second War.