Don’t need two on the same topic, especially since one is super messy.
Converse with fellow players
You can't. All you can do is flag the first post for moderation and leave a message for the GMs about it. They will normally either lock it or delete.
You can't personally, but GM has closed threads saying the topic starter ask for it to be closed.
You can flag the initial post for moderation - and use other/specify to tell GM you are the topic starter and would like it closed.