[@robin-w Moderator 11 years, 7 months ago]

ok,

1. not possible with bbpress as far as I know
2. only admin/keymasters get this priviledge
3. https://codex.buddypress.org/getting-started/installing-group-and-sitewide-forums/
4. If I understand the question correctly, normal users – that is the default ie participants can create topics and replies, but not forums or categories. If you meant something different then come back