Not put very nicely, but it's true - I run Intel CPU and AMD GPU seamlessly.
For Arma 3/DayZ (same engine) the most optimised CPU is always Intel, hands down. For basically any other game, AMD is considered more of a gaming CPU. The Arma engine is just a fickle bitch and is only fully optimised for Intel.
With that said, I reckon the best advice you can get is to go to the BuildaPC Reddit - http://www.reddit.com/r/buildapc/- and put your build up there with the correct tag - [build Help] in this case and they will not steer you wrong - there's some parts wizards on that page.
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Edit: just saw the rest of your build and I'll just offer some advice in case you were unaware - If you have already bought the parts, just disregard the rest of this as there's nothing worse than second-guessing yourself! Your rig will run fine, I'm just offering a few money-saving/better value/better performance parts and techniques.
16GB RAM is great, but just make sure you get the fastest you're willing to fork out for and don't be concerned about brand for RAM - it really isn't important, the cheapest brand is fine. In my case, it was Patriot I believe. Also, as you probably know, you'll want to get 2x8GB cards rather than 1x 16GB cards and make sure to put them in the slot 1 and 3 or 2 and 4 for optimal performance - prevents bottlenecking, allows greater power.
The OS SSD seems like overkill to me - do you really need all that space for an OS? If you're getting Windows 8.1 (my recommendation), then that takes up roughly 20GB. Also...I personally feel the brand you're using for that SSD...you might want to upgrade to a samsung EVO - those suckers are awesome. Just putting it out there, but you may get away with fitting it on the 1st SSD along with the games, freeing up some money for the GPU if you can afford the space with the games.
Also, Seagate should be a cheaper HDD and I really used to expect them to fail all the time given how cheap they were, but they are damn good, never had an issue. If it's cheaper than the WD (which I have heard some bad things about failing from a pro builder) I'd highly recommend switching it out.
Other than that, good luck and I hope it all goes smoothly for you, brother - take it easy.