You won't get 60 FPS everywhere, all the time.
Dalaran, Wintergrasp and some battlegrounds will have noticeably lower FPS.

However, the game will be very playable everywhere.

I have a similar system.
Same processor, ram is the same speed although I have more, my video card is worse then yours, my SSD isn't as good...
And I 5-box smoothly enough everywhere.

With epic flyers, unless I cross phase lines, I can only break follow if the Paladin is the lead character and Crusader Aura is on.
Anyone else leading, or no Crusader Aura on, or Crusader Aura on a follow and I cannot break follow.
AV is smooth, even with 40 toons at the starting area.
WG is easily playable.