I managed to reinstate the forums by deleting and reinstalling plugins in a particular order. It didn’t seem to work if they were installed or updated in a different order even if the end installed-active list was the same. I’m running genesis theme with a child theme and the issue started with upgrading to WP 4.7.
Here is what I did which solved it, I do not know why (unfortunately):
1. using ftp, I overwrote bbPress plugin with an old version dated 5/6/2015
2. in the wp-admin area, under plugins, update the plugin to the current one
3. in the wp-admin area, search for, find, install and activate the plugin ‘User Role Editor’. then the ‘Forums, Topics, Replies’ appeared in the sidebar of the dashboard
4. then I could open tools/forums and could see the forum-fixing items here: https://codex.bbpress.org/features/tools/repair-forums/
5. magically all seems to work now