Edid information

There is a tool called read-edid doing exactly what its name suggests.

Try xrandr --verbose. It shows the RAW edid information and lots of other useful information for all monitors connected to your computer.

Example output, with only the EDID section:

$ xrandr --verbose
(cut)
    EDID:
        00ffffffffffff0030ae364000000000
        00130103801e1378eaef259458568a29
        24505400000001010101010101010101
        0101010101018a25a02051841a303040
        360030be100000195e1fa02051841a30
        3040360030be100000190000000f0095
        0a32950a2816090030e47302000000fe
        004c503134315750332d544c413100ab
(cut)

With regards to your last question, udev can inform you and let you run commands when a monitor is connected. It's really easy to write bash scripts for udev events.

I'm not sure what you're trying to do here, but I find xrandr very useful for automatically setting the monitor layout that I want whenever I plug or unplug external monitors at work or at home. You don't need monitor serial for this. The simplified output name works fine. Run xrandr to see the outputs (monitors) available.

I run this script to set my preferred layout:

#!/bin/bash 
xrandr --output LVDS1 --auto
xrandr --output DP2 --auto --right-of LVDS1

LVDS1 being the name of the notebook monitor, DPS2 the external one.