Congrats on geting the wiring / test prints. hair spray seems to work, but we also are using cyanoacrylate (CA) and insta-set to quick dry it. It requires some eblow grease to remove but your prints will not lift. Just dont get too much CA on the actual print as it can mess up layer adheasion.

Now, for the LCD...is there a +5v or ground symbol on the mainboard and on the LCD? What about a tx+/- (could be rx+/-)

I did a quick search, but all references I have found to LCD's have had a different wiring harness than you described