I don't see Gen 7 coming out in 2016. First off, 6th gen will last until the end of the year, on average the episodes per season is 48 to 52. Sometimes more. The movie doesn't come out till July and I just don't see them bringing out 2 sets of games in the same year. I don't think there is any hope, what so ever that the 7th Gen will start next year. We might see 7th Gen pokemon, but that is all.
If I had to guess, I would say Pokemon Z will be between Early Spring to Later Summer or so. These are the American release dates. Japanese is usually earlier other than the past few games.
Red and Blue - September 28, 1998
Yellow - October 18, 1999
Gold and Silver - October 15, 2000
Crystal - July 30, 2001
Ruby and Sapphie - March 17, 2003
FireRed and LeafGreen - September 9, 2004
Emerald - May 1, 2005
Diamond and Pearl - April 22, 2007
Platinum - March 22, 2009
HeartGold and Soul Silver - March 14, 2010
Black and White - March 6, 2011
Black and White 2 - October 7, 2012
X and Y - October 12, 2013 (Worldwide Release)
OmegaRuby and AlphaSapphire - November 21, 2014 (Worldwide Release)
March, September, and October a are the main months it would seem. With this knowledge and the movie coming out in July.
March 12th or March 19th for Z is my best guess.
And Pokemon 7th Gen will probably be in March or October 2017. This depends on if there will be a 4th movie in the 6th Gen, which I think there will be, in which case it will be October or November 2017.
Japanese dates would be a better indicator than say American dates, as Japan is the main focus...
In Japan it's usually September.
Pokemon Red and Green- February 27, 1996 (remaster on the same day, 2016)
Blue- October 15, 1996
Yellow- September 12, 1998
Gold and Silver- November 21, 1999
Crystal- December 14, 2000
Ruby and Sapphire- November 21, 2002
FrLg- January 29, 2004
Emerald- September 16, 2004 (first time since Japanese Blue that a game came out the same year as a another pair)
Diamond and Pearl- September 28, 2006
Platinum- September 13, 2008
HgSs- September 12, 2009 (barely a day off from Pt's one year anniversary)
Black and White- September 18, 2010 (at this point Japan got three games in a row in september for three years)
Black 2 and White 2- June 23, 2012 (first time that Japan didn't get a game in September since 2004 when FrlG came out...)
XY- October 10, 2013
OrAs- November 21, 2014
As you can see late Summer (the early september ones), and Fall are the usual release times. None have come out in Spring, while Winter has RG, their remakes, and their releases (Crystal came out in late Fall)... Since we're getting releases I would count out Winter, and Spring is a main game dead zone...I would say that Summer 2016 (anytime between late June- mid September is fair game) is our best bet for a release that isn't fall.
heart gold & soul silver came out after the 4th gen had ended and were made to stall off time until the 5th gen came.
All the remakes other then OR/AS where made to add the 2 gen that were cut out of the connectivity of the games back in and update their stat system.
kinda need to add something to that list:
Red and Blue - September 28, 1998
Yellow - October 18, 1999
Gold and Silver - October 15, 2000
Crystal - July 30, 2001
Ruby and Sapphie - March 17, 2003
FireRed and LeafGreen - September 9, 2004
Emerald - May 1, 2005
Diamond and Pearl - April 22, 2007
Platinum - March 22, 2009
HeartGold and Soul Silver - March 14, 2010
Black and White - March 6, 2011
Black and White 2 - October 7, 2012
X and Y - October 12, 2013 (Worldwide Release)
OmegaRuby and AlphaSapphire - November 21, 2014 (Worldwide Release)
Red, Blue, Green(japan only) & Yellow anniversary redux February 27th 2016
Uh, the remakes are part of the gen they come in too, so HgSs were the end of Gen IV. Btw OrAs was only a semi-world release in the major countries, as it come out in Europe on the 28th or sometime around there.