Question 1
The activity stream shows in 2 places. One is the users profile (tab) and the other is through the cb plugin menu item.
Both streams are showing fine but the commenting ability only exists in the tab. The cb plugin menu item page does not show any field to comment at all. Am i doing something wrong?
Menu streams use the parameters in the menu item. By default they will just inherit whatever you've set the parameters to for Activity in CB Activity > Parameters (these are the Global parameters). Review your parameters carefully. If you adjusted things in the Activity tab in CB > Tab Management they won't have any impact on the menu usage.
Question 2
We want all registered users to be able to comment on activity stream items, but only the user that made the stream post to be able to see the comments.
Is this doable?
No, not without custom coding in a custom template file.