I've heard that there will be a new alu' and carbon 2018 Diverge with the Future Shock system. For the Roubaixs, Specialized are charging a premium price because it has the Future Shock and there is no alu' version of the Roubaix. The Diverge pricing is likely to be similar - significantly higher price for the 2018 Diverges than the 2017 given the same equipment. Given the price increase needed for the Future Shock models, I doubt there'll be a budget option available, I expect that they'll keep the 2017 alu' Diverge for that without the Future Shock. Since the alu' Diverge Future Shock is likely to be at the higher end of the alu' bike price range, I wouldn't be surprised if they equip it with Shimano 105.
I'm not sure how much longer we're going to have to wait for official details on the new Diverges. Specialized will be launching the new Tarmac shortly before the Tour de France, and they'll probably want to give the Diverge it's own separate announcement. The availability of the Diverge needs to be relatively soon since they've already ran down the stock of the 2017 Diverges and there are none left to order in most markets. This all suggests that the launch is imminent and availability should be not too long afterwards. Also, Bicycling.com isn't the sort of website that would publish that "unofficial" photo without first checking with Specialized that it was OK with them, so Specialized must be planning to officially launch it very soon.