1. That's a quick fix. We just need to duplicate the "tweet" infrastructure in the community with a new event kind so that a post can be exclusive to the community.

2. I don't think that's confusing at all. If I follow a person, I want to see everything that person does, including new submissions to a community. I want to see all chats, all messages on live streams, etc.

3. Even if you make point 1, clients can still opt to show in the regular feed. You will never have the control to not allow posts to get out of the community.