I think it would be helpful if you could hover over the buildings at any time and have a pop up in the UI telling you what they are. But it is definitely needed while demolishing!

We should be able to demolish from the city list anyway, it would be much faster to demolish buildings with maintenance.

If you actually try to demolish a building, it will prompt you, asking "Do you really want to demolish <building type>?"  You can then accept or decline.  As far as I know this is the only way to tell what an individual building is.

I definitely agree with this.  As a city builder, I'd like to know (not that it matters except in my own mind) that I don't want to place the gallows right next to the merchant or inn, might depress commerce.  Also, when I conquer a city I'd like to have an easy way of discovering what buildings are already in that city without having to go to the city details view.