This topic is titled as “Chat View” but seems to have become a discussion about possible technical implementation details. I think it would be better to identify the use case that is to be addressed without focussing on how it might be achieved.
Chat View as a topic sounds like a new type of data view.
Whether the underlying data is an entity from a specific sidebar database, or an entity in the comments ‘database’ (see here) seems beside the point, if this discussion is to be had about how best to display ‘comment entities’.
Similarly, the ability to control who can/can’t see a comment is tangential to any ideas about visualisation of the comments themselves, and seems to be the topic of discussion here.