Some interesting stuff here!
First, Project Guard and Giant Robot. Looking back, it seemed like Giant Robot used some of the same concepts as Star Fox Zero does, with two views on the TV and GamePad and hybrid control scheme of buttons and the gyroscope. I suspect as Star Fox Zero comes out, it will be subtly hinted that Giant Robot was incorporated into Star Fox and Giant Robot will somehow disappear. Project Guard looks more like proper vaporware, though I could again see it being incorporated into another, larger game. I wouldn't be surprised if Zelda U included some sort of Tower Defense minigame.
Japan's lineup is a bit mixed for the rest of the year. There is no guaranteed megahit from, especially considering how variable Super Mario Maker's fate may be, but Pokemon Mystery Dungeon, Mario & Luigi, and Happy Home Designer will all sell well enough on the 3DS. And for once, third party support may be superior to Nintendo's offerings, with Monster Hunter X, Yokai Watch, and Dragon Quest 8 all being notable releases. The Wii U lacks much of note besides Super Mario Maker, especially since Star Fox is not particular popular in Japan, but at least Mario Tennis and possibly the Fire Emblem crossover should do well enough.
America is a bit better off on the Wii U and a bit worse off on the 3DS in comparison. Pokemon Super Mystery Dungeon, Triforce Heroes, and Yokai Watch will all do well enough, but there is no major game coming from third parties like in Japan. The lack of Mario & Luigi or Fire Emblem Fates also hurts. However, in addition to Super mario maker as the main pusher of hardware, Star Fox is most popular in America. Third party support is also a bit better in America, considering how games like LEGO tie-ins, Skylanders, Disney Infinity, and Yust Dance do decently even on the Wii U.
Europe is probably the weakest region. Pokemon Mystery Dungeon and Yokai Watch being delayed into 2016 is harsh, arguably leaving the 3DS without any big releases this holiday. The Wii U situation is like America's but with no Yoshi to round out the calendar and Star Fox Zero being less valuable.
Nintendo's primary worries for late 2015 need to be the Wii U in Japan and Europe as well as the 3DS in the USA and Europe. The Wii U needs a price cut to roughly $250 and/or bundles that have more value. A $300 bundle that features a Wii U with New Super Mario Bros U, New Super Luigi U, and Super Mario Maker on a single disc would be an incredible value and tie together all the similar content Nintendo has made for the Wii U. The 3DS could get a price cut, but hardware releases seem like a better choice to me. Maybe the 2DS could finally see a Japanese release as a budget form of the hardware, and the standard New 3DS could be released in America, especially if the original model is completely phased out. The plates could do well in America, giving Nintendo a bit of extra room to work with.
