I saw that some friends know who are the search committee members before their interviews. So would it be fine to ask the department who are they? And if it was fine, why the department didn't mention their names since the beginning? Could asking about their names be taken as negative thing?! A strong applicant could say that she doesn't care who are finalizing the list or interviewing her.
In general, I would recommend against asking who the search committee is. It might give the impression that you are trying to "game the system" rather than simply put your best foot forward for everyone. That said, I don't think this is a serious faux pas.
Some departments, including my own, post a list of committee assignments on their department homepages -- mostly out of convenience for their own faculty. So you might be able to answer your question without asking.
Depends on the culture of the field. In economics, the placement officer told all candidates from our PhD program to ask who the interview committee members were when receiving a call or email offering an interview. Sometimes the question was not answered or the answer was delayed, sometimes the committee was on the website of the hiring department.