Attorney wanting to provide value ahead of time

Hi Brooke and team, I am launching a law practice offering estate planning services. My niche is single women in their 50s. My thought for providing value ahead of time is to invite potential clients to a free webinar that educates them on the need to have a will, power of attorney, healthcare agent, etc. For potential clients who want to go farther I would also offer a way to receive a free 2-hour planning session with me with no strings attached. Also, I’m considering purchasing a booth at a Women’s Expo that attracts 10,000 plus women. The main goal is to build my email list and also hopefully attract potential clients. I have four questions: (1) Do you think that my niche is narrow enough? (2) Do you think the free webinar and the personalized free 2-hour planning session is enough value being offered ahead of time? (3) If I participate in the Women’s Expo I was going to have a drawing for a nice prize that my avatar would like. Would this be the best way to secure email addresses for my mailing list? (4) My understanding of marketing to your niche is that you don’t call them out specifically but you speak their language and hang out where they congregate. That being said, I would still like to put up some kind of sign at the expo that uses the words “single” or “single women” to attract them to my booth. What say you about that?
Thanks in advance. I really admire your business acumen and I think you are pretty great!