bbPress can be network activated so each subsite can create forums but I’m not sure if the site wide forums option in BuddyPress can be network activated.
BuddyPress only works on one site in a WPMU install. bbPress might be more flexible with multi-site but I’m not sure. There is a plugin that will allow each site to have its own BuddyPress install but I think that would be problematic to maintain.
What items are you adding? Only profile links are hidden when logged out. If you add a link to say a forum topic it won’t be hidden.
There is a way to hide links. The current release is experimental. In next update there will be more items to add to a menu and I’ll explain how to hide other links on log out.
Please be patient, I’m testing different things to make it the best it can be.
Instead of BP including a header.php sidebar.php and footer.php the plugin will only include a partial template file. So it will fit into most any WP theme.
Out of the box we must include a base layout/style to make it look ok or people will just delete and call it crap. You will not be stuck with this layout, you can override the css or use your own template files in your theme.
I wouldn’t mess with a plugins code but work around it. You could write a function to redirect user to profile edit page if certain fields are not entered in the profile edit form.
You would have to write a function that loops through all activity finds the string #whatever and then returns a count. Not difficult at all if you know php.
If you are using bp-default you can install BP Extended Settings plugin. There is option to turn off responsive css. You will still need to add some css that forces a minimum width so the content doesnt get scrunched up.
You already know how to get it, your code may not be correct or enough to use it to do what you want. I did not try it, if I have time I’ll look into it. Is this really the loop or just each group?
Another option you may want to try is to remove the item for every one then add it back for just admins. You may have to write a bit more logic to your code:
if (on the current group && current user = group admin)
add sub nav
