Bombing towns/cities is BAD. That's known fact and stands as
sabotage when done with malice.
However you can manage your
claimed town as you want, allowed to destroy statues/fountains/parks or any houses that aren't placed as you designed the road layout (for example). About public cities (marked as .: City :.), it's recommended not to destroy statues/fountains/parks for the reason that in the logs will only show that you "cleared the tile", not showing what was there when you bombed it. About the rest of the buildings fits exactly on rule #6.
About the interactions with towns/cities (advertisement, statue), it's perfectly legal to do any of it.
I think it's all. If any doubt remains, feel free to reply.
Note: I moved the post to the sub-forum about CB