Have enough with mining, transform my mining rig to make 4K gaming rig?

[Kenshin]

I have enough with mining altcoin. I currently have 2 rig, here are the specs:

Rig 1:
Intel Celeron, running 2 x 7950. MSI Z77A-GD65 Motherboard. AX860i PSU

Rig 2:
Intel 3rd Generation Core i7-3770K CPU (4 x 3.50GHz, Ivy Bridge, Socket 1155, 8Mb L3 Cache, Intel Turbo Boost Technology 2.0), running 1 x 7970 and 1 x 7950. AsRock Z77 OC Formula Motherboard. AX860i PSU

I am thinking of stripping the Rig 1 GPUs and move them to Rig 2. And then get a smaller case for Rig 1 to just use this as a desktop computer.

For the Rig 2, with the combine GPUs I will end up having 4 GPUs on one gaming rig. I am going to get a full gaming tower case (Coole​rmast​er HAF Stac​ker 935 Larg​e Towe​r), looking for a motherboard which support 4 GPUs, the mobo I got at the moment only support 3 GPUs.

Here are some questions about the transformation of Rig 2, as I am not really that good with PC hardwares. So please give me some suggestion.

1) Should I get the Corsair AX1500i PSU, so I can have more than enough power to potential upgrade to 2 x Asus Rade​on R9 295X2 or in the future?
2) If I change the mobo to Asus Maximus V Extreme will I be able to use 4 GPUs? If not can anyone recommend a good gaming mobo which support 4 GPUs with Socket 1155 CPU.
3) I am going to get Corsa​ir H110 Hydr​o CPU Cool​er for the CPU. And with this case I read that I can put lots of fans in this case. If I am only going to play games on this rig, will the cooling be enough? If I can help it, I don't want to touch watercooling of the GPUs, I am not that good with hardware, I might end up flooding the whole rig.
4) With 1 x 7950 and 3 x 7950 I read that I can Quadfire them together. Will the graphic be 4K?
5) Also I like the new Nvidia Shield Tablet, do I need to have a Nvidia GPU to connect to this tablet? If so I might end up getting 2 x Tita​n Z when they drop the price.

Please help, thanks