I have a good relationship with my PhD advisor that extends a little beyond the strictly academic (nothing inappropriate - for example I have met members of her family and she has let me borrow her car on occasion). Would it be appropriate for me to invite her to my life cycle events? (e.g. a wedding or a ceremony for the birth of a child)
Given that you already have a relationship, I think it is fine. There doesn't seem to be any hint of impropriety here.
I wouldn't have done it, but my advisor was very aloof (er... distinguished). But There were several other members of the faculty, some on my committee, that I was happy to interact with in many ways outside the academic setting.
I'd guess they would appreciate an invitation and it builds a kind of trust that can lead to collaboration throughout your career.