The wording is all a little vague - especially broken into separate quotes in the article. For one thing, the number of things is a bit vague from "a couple settings" and "two surprises this summer" but possibly a (third?) different surprise they are announcing in July??
Also, nowhere does he state that any of these will be hardcover releases or physical products of any sort. Given the way the publishing industry works, I'd say a hardcover, or even any printed book, this summer has Zero chance of coming out. Another hardcover at the end of the year also seems unlikely at this point but that's still being debated to death elsewhere so I won't get into that.
Since no retailers or distributors are showing signs of other physical releases especially this summer, I'd presume Planeshift/EEPC style PDF releases. Not to mention that earlier this year Nathan Stewart said they had exciting plans for DMs Guild this year. So some PDF releases on DMs Guild as introductions to the settings in 5e (and hopefully opening up DMs Guild to 3pp products for this settings!) seems to be a lower cost and less risky way to satisfy a lot fans without competing too directly with their hardcover sales. I would be incredibly amazed if they were another hardcover(s) rather than DMs Guild PDF releases.
