My take is that our role, as parents, is to instill self-confidence and self-esteem in our children so that they can independently weather the inevitable loneliness that comes with being...different. Your daughter sounds wonderfully well-adjusted, so this is probably redundant.
Yes, but, depending on the person, without a certain number of close friends, you may or may not be able to function adequately.
I don't think this is an issue of self-confidence and self-esteem as much as it is a function of being human and having social needs.
