Hi Matt -
All team members have their names in different colours - Red for admin, dark blue for supermods, green for mods. There's also a pinned post called "Meet the team" so you can know about us too.
Double posting - posting twice on the same thread within 10 mins is the rule we use. I just ask that people don't do that. It's terrible for continuity, some people only do it to increase post numbers to get past newbie stage etc to be able to post links and pictures, it's better for our data if double posting doesn't happen and many other issues.
Members - yes all registered are members, only team can edit posts.
Members can't edit posts for many reasons - for example, 1ce we had a member who would write something and then go back and change everything to remove what they had said. This may not seem like a big issue, but it is for continuity, for the fact that this person was someone I was used to dealing with their care team about. Once they'd changed their posts, the "evidence" had been removed. Another issue is for spammers. We've had it where a member posts, then goes back later to change it to spam - links and pictures. This may not seem a problem, but trust me some of the things I've seen make me uncomfortable and I'm about as far from a prude as it's possible to be!
Hope this helps to explain things. Every forum has their own rules, this is just one of mine. We don't have many rules and are pretty open and relaxed about most things.