Okay forget all questions, I have overseen the manual, in there all answers are placed.
But one question I have, is:
What about loading plugins for jquery, these plugins uses $. How can I handle that? Should I overwrite $ in all jquery-plugins or is there a better way?
Looks like yes, you should replace all $ with jQuery
Recently I had to go with option E. I embedded textarea autogrow plugin which contained $ in source code. It started to work after I had replaced all the $ occurences with jQuery.
I've read some jQuery forums and it seems for me that jQuery plugin developers consider using $ in plugins as a bad practice. So I suppose you should go to jQuery bugtracker and create a ticket against the plugin you use.