You're starting to get very far afield. I'd recommend that you focus on the topic of this thread; if you want to start a new topic on multi-monitor fullscreen apps with LWJGL, that's a better idea.
I'm not sure, but I've always assumed that multi-monitor fullscreen was something the graphics card did on its own, not something that applications managed. A quick look on Wikipedia seems to support this (http://en.wikipedia.org/wiki/Multi-monitor#Span_or_extended_desktop_mode
). However, there does seem to be a mention of how you can explicitly program such functionality (http://en.wikipedia.org/wiki/Multi-monitor#Programming
As to your idea, that's what I was alluding to, yes. However, AWTGLCanvas is the only way to have multiple display surfaces concurrently in LWJGL, and it's been very unstable when I've used it. Additionally, you need to impose some sort of artificial mechanics to prevent one of the windows from being moved, minimized, closed, etc. without the other following suit.