(1) I don't think that some questioning would be out of place. I think there are different interpretations of what message a particular passage in the book means. If you are talking about questioning the validity of the passage itself (i.e. it being wrong), I dunno. I'm not saying you would be wrong to do it, only that it would be like questioning the validity of a passage in the bible at a bible study.
(2) Can't help you there, I have yet to hold a position in a group.
(3) I have been taught (and agree) that the parts of the BB that are in italics are more important. Italics were used sparingly in the BB, and when they are used it is to stress the importance of what it is saying.
(4) I have no opinion here