The "posting in" can be nullified by setting the variable:

set text_posting_in = "";

(and then targetting the user tags in the userpic div and making them display: block).

And then the subjects in comments, remove this line from Gradiance:

set all_commentsubjects = true;

re: 4.) hmm, which text do you want to change? I think we're keeping that the same across
official styles so people can navigate easily, but I may be thinking of something other than what you're referring to



re: 6.) set text_tags_item_sep = "";



So I guess just 2.