By all means feel free just to chat in the guestbook - as long as it's not spam!
Anybody with Admin below their name is definitely me or a trusted person. I myself will always sign as Butterfree. If somebody signs under that name but does not have the Admin label, it is most likely an impostor.
I realize there was a leak and the fact it's proved accurate so far means it's highly likely to be accurate about the rest, but I'm not putting names on here until they're officially confirmed, as a matter of policy.
In case you didn't see, all of the new english names have been leaked a month ago: