Didn't find some features among the sea of el's in the emacs world. Thus implemented them myself:
(1) (Almost) real time character counting. This includes counting of the whole buffer, and the counting of the present section (defined in the org-mode sense).
As I am mostly writing Chinese, character counting instead of word counting is good enough for me. Word counting should be possible following a similar way.
The counting is displayed in the title bar. I am actually hiding the mode line to avoid distraction. Thus the title bar is the only place where indicators can be shown.
(2) Focus edit on one section, hide all other parts of the document. Of course one can re-focus on the whole document with another key stoke.
The code is shared .