My iPhone does 4K
the in body intervalometer is also a nice feature, I haven't used Lightroom before but if they add the duel pixel raw, I think it will be useful when I use the 85 1.2, if you just miss the eye, you might be able to salvage the picture, I'll just have to remember to turn it on and off when switching lenses.
Also, swivel screen isn't necessary is it? you could just use your smart phone connected via wifi, a hotshoe ball head with a smartphone grip would give you a hands free external screen that will swivel any way you want.
Using quidco will get you £100ish off the price too if buying from wex, if anybody had forgotten about cash back.