PC upgrade -new MB & PSU

Thanks to premiere of gtx 1080 Ti im planning to upgrade my PC to second (and some time later third) card.
Current setting:

  i5-4690k
  MB - z97 - Mini itx (one pcie 3.0 x16)
  16gb ram
  GTX 1080 FE
  PSU – 650W gold

As you can see this is not, in any case, good machine for HC  but – 1080FE is 1080FE J.
Since it is 1150 socket I can't see a point to upgrade to z270. Upgrade to X99 would best choice but it is far more expensive.   
Here is what I come up with:

  i5-4690k
  MB – ASrock Z97 extreme 4 (3 slots pcie)  (x8/x4/x4) http://www.asrock.com/mb/Intel/Z97%20Ext...dex.pl.asp
  16GB ram
  GTX 1080 FE and GTX 1080 Ti FE
  PSU – Seasonic PRIME Platinum 1200W (SSR-1200PD)

Here comes questions:
1.      PSU - will it be enough for 3 cards  1x GTX 1080 + 2x 1080 TI (TDP apx 1000W)? Any other/better options?
2.      What do you thing about MB? This ASrock is the best one I find.

Thank you in advance for any response.