I would like to add two more to your list:
Youth Watchtower Study. My congregation, back in the early 80's, had a number
of young people who got together weekly to study their Watchtower, and have a
little gathering afterward. It was shut down by official word from the Society. It was
possible for it to become a forum for independent ideas.
Internet sites. When the internet first came out, Witnesses would get together to
fellowship on-line. We all know what happened to that.