Open source forum / discussion PHP / MySQL - Vanilla forum

Forum / Discussion functionalities:
1. Based on PHP / MySQL ad vanilla - https://open.vanillaforums.com/download
2. Private forum with access to members with login/password , but no free registration (disable), registration of members by the admin only at this stage
3. Email notifications
3.1 to all members when there is a new discussion posted on the forum (to any of the categories)
3.2 to members participating to a same discussion
4. Members who did create a discussion are only the one to close a discussion
5. Moderation disable
6. Minimalist stylish theme
7. Registered members are to be grouped following 3 customs sub groups: ASEC / ASEAN Sectoral Bodies / BACs
8. A custom tools is to be developed and/or added to monitor total of threads, total of replies per sub groups with list of thread + replies per member of sub groups as well

Development on your server at first.