Based on some new evidence on Screamscape, it sounds like a GCI is a done deal. There are also rumors that the park might be bringing back their Christmas event next year.
New Coaster - Rumor - (7/7/16) Kings Island has been teasing on social media by showing off images of trees being cut down along the new pathway for the rapids ride over the past week to generate interest in their 2017 coaster project. While we've been sure since the plans leaked that it would be a wooden coaster of some kind, no one has been 100% sure on who was building it. Though a reader spotted something a few hours ago that would seem to lock it down, as they spotted a truck pulling a work trailer into the backlot area of the park that had the initials "G.C.I." on it. Sure sounds like this will be a GCI coaster project then if true, and honestly based on the plans leaked, it really didn't look like an RMC anyway.
Park News - (7/7/16) Is the return of Winterfest planned for Kings Island? Last week we heard rumors of it being discussed by management at Carowinds, and now we're hearing that some initial discovery and early tech work is underway at Kings Island for a possible return of the winter event in 2017.
There is also talk of some kind of Christmas in July special event expected to take place later this month. I'm not sure if they would use such an event to make an announcement for a Winter 2017 event, but they could take advantage of it to take some guest surveys and marketing studies I suppose.