Played around with it for a while, and everything seems to be working fine from what I can tell. I liked all of the modifications/improvements that I noticed. There were just a few quick things/ideas that popped into my mind when I was testing.
1) Maybe it'd be good to have a message pop up in chat when a trade is either completed or canceled. Just a simple "The trade was successful" or "The trade was canceled". It seems to end a bit abruptly, without being clear whether the trade was canceled or successful. (might've been because I was dual-clienting, though?)
2) Is it safe to edit the chat commands in the script? I'd like to shorten /gmsg to /g for ease of use.
3) You probably had a reason for this, but wouldn't it be better to have the guildname display above or below the character name, instead of next to it? I managed to make a nameplate that was nearly long enough to cover the whole screen.
Of course, this can be toned down by limiting the amount of characters allowed for a guild and login name, but having the guild name above/below seems more intuitive anyway. This is not really important though, just mentioning it because I thought of it.