5. The computer code evolves, Adobe might fix the bug in their SW, but not in library used by Onyx. That bug is not for all pdf, but only for some of them.
6. You are right, there is not functional
difference between Selection Zoom and 2 points Zoom. The only difference is, how you specify the zoom. I do not use it any more, but when I used it, I used mostly 2 point Zoom, as it is faster.
My opinion is, there is space for Selecton Zoom, if you need make perfect cut, but it should be implemented (in user interface) the same way as Universal Manual (crop page).
I agree, the interface needs some kind of polishing. It is not very intuitive and without manual it makes understanding even harder...
But one has to understand that we are in "transitional state" Features are added/removed and to make manual is often more work than entire programming, so I understand that they want make update of manual when big changes are finished. I hope it will be soon.
I do not use DRM, so I do not know. I guess you insert there username and password and it allows you to read DRM material.