I would consider the D5 an investment, for most systems its all you will ever need.I wish those kits where about when I started watercooling. Mine cost a hell of a lot more than that.
Yes the 750 can support CPU + a GPU.
If he used the list I gave in the first place with the 4GB card (04G-P4-2673-KR) and the D5 kit.
Total 1518.72. + distilled water, tube and killcoil.
The 670 and the i7 will by fine under the rx360. My i7 and 580 are hotter than those and I use 750rpm fans and my rad is a ek 360 which is thinner than the RX.
If you SLI down the road then with my list all you will need is the other gpu block and another rad. rx120 or 240 depending on your modding skills.
By the way op.. you missed the ram off the amazon order.