I like the idea of having diverse chatrooms in this website, but the problem is that the community here is not much interested in doing chats. At the time of posting my answer to your meta post on July 01, the last activity on the Academia's chatroom was on about nine days earlier June 22. That is why I think that the Academia's community does not find chatrooms useful indeed because it is not using it very often; so making more chatrooms seems not to be feasible.
Despite the fact that eykanal correctly mentions that most of the discussions take place in Academia's meta; I see no interest in organizing chat events too.
About your first question; at our current chatroom, unfortunately very few discussions happen about closing or reopening posts on our main site. Those are discussions usually made not by the people who vote to close/reopen posts, but by the users who think that their post should not be closed/edited.
So, at our current state opening a new chatroom will not encourage users to join chatrooms just to discuss moderation activities which happen on Academia's main site.
These are the signs that bring me to the point that although your suggestion is perfect, the community seems not to be interested in doing chat in Academia.
However, in order to improve our community here, we can think about how we can attract more people to the chatrooms (for example, by organizing events, which I suggested before but never received enough attention by our community: Event Proposal: Decide on Unanswered Questions) or think about why people here are not really interested in doing chats compared to other Stack Exchange sites.
After chatrooms had a minimum number of users who think that chatrooms are useful on Academia, and discussions needed more specific moderation attention, then it will be feasible that we make more chatrooms.