I can kind of answer those questions. Three things first that make my situation different.
I come from a video background but do photography on the side but not professionally (yet). I just got the Zeiss 85 1.4 ZE this week so my impressions are fairly new. Lastly, I'm using a 5D mk iii with the standard focusing screen.
Now my answer.
1) I find the zeiss 85 to be a little harder to manual focus (especially at 1.4) than my other zeisses (35 and 50) but overall it is still easily doable. You just have to pay attention more closely. This is most likely due to the smaller focusing plane on the longer lens. I think...
2) I have used in the past the 85 1.2L and in most cases I think they are on the same level. For portraits they give off the same overwhelmingly soft bokeh while still keeping your focus sharp on your subjects face and eyes (at 1.4). A feat not many lens can do. The 1.2 vs 1.4 to me is almost gimmicky and useless. Another fact, the size of the L is larger but the front elements are actually the same on both. The L just has plastic casing around it concealing the autofocus.
Lastly if you do video, the L is useless when you try to manual focus with it. The focus ring is nearly impossible to dial in right as it spins too fast and loose.
Hope that gives something!