This is very easy to answer. The Nvidia GT 750M offers 2GB of VRAM, the new macbook pro can be configured with 4GB of VRAM. For Resolve and 4k nothing but the maximum will satisfy you.
Great! That's missing in b/w films today, where the photography is done in color and then simply the saturation is set to zero in the postproduction including "Nebraska".
do you know this page? follow the instructions and everything will look fine!
horrible background music
Buy the 2015 iMac maxed out and you will be happy, the iMac 2015 is fast enough for 4k editing. What do you expect from a new iMac? It will be a little bit faster than the 2015 iMac, but only in the limits new mac's get faster with every update, like 10-20%.
to be exact, the crop factor of BMPCC is 2.88