1. I'm not sure which is more important for her, but I do know that the school's culture is a major factor in her decision. Of course, different schools have different "flavors" or personalities, so a lot of what I'm asking is whether it is true that Berkeley has a more laid back atmosphere (relative to other schools, if this comparison can be accurately gauged) or whether HLS tends to be "stuffier" or more pretentious. Having one poster comment that s/he wouldn't like my friend (who I have described as generous and passionate) to attend Harvard with him/her certainly reinforces the snooty Harvard stereotype to some degree, though obviously one person's comments are not indicative of an entire student body.
I wouldn't want to attend with your friend because what you call "generous and passionate" sounds naive and unrealistic to me. You have to understand that people with some vague interest in social issues show up here a lot proclaiming their disinterest in biglaw or money, and well, I just can't help rolling my eyes, because it sounds so damned uninformed.
Which is why I originally said that she might not want to go to law school, but as you already pointed out, I don't know her personally, so I can only go on what you've said.
3. I would imagine that job prospects from both schools are excellent, with Harvard perhaps winning out somewhat over Berkeley. However, I described her partially in order to indicate that she is not and never will be interested in a biglaw job. This is not to say that Harvard students are only interested in such jobs - they are obviously not - but she would like to attend a school in which biglaw prospects are less dominant (relatively) and "alternative" options are more prevalent. That is mostly why I described her as unconcerned with prestige - she is not looking to choose the best "name brand" in order to secure one of those high-paying, biglaw jobs. We went to an Ivy undergrad together, so she is (we are) perfectly fine with being around others who are very "prestige hungry" - and I think someone who attends an Ivy or is even considering Harvard Law School values prestige to at least an extent - but it is certainly not the only, or even the most important, factor in her mind.
It's harder to get permanent, full-time public interest jobs than biglaw. Which is why I said above that your friend sounds naive. It is a mistake to think that one's non-biglaw interests mean they have more flexibility in selecting a school. IMO it's quite the opposite.