Made great progress today! Finally was able to see the graphics and videos although some images did not show up. Below please find my response:
First I would ask, are you using a normal wired keyboard?
It's a wired USB keyboard. The fact that it actually registers all key presses when setting up a "custom 1" key makes me feel that the keyboard is seen by the program.
The issue is only at a "input text box" type widget, where it does not echo any text typed. The backspace/home/end/arrow keys do work in the text box.
Second I would say, you can manually modify the attract.cfg (it's just a text file) "input map" fields to see if that helps.
I can see the auto generated "input map" section and those keys do work. Again it's only in the text box that I cannot type.
Third, you can manually create emulator files, but this shouldn't be needed.
This is what worked for me. So I created a MAME.cfg file using your template. Then upon entering AM I can see an emulator "MAME" appears in the menu.
There is some small issue though: The logo and marquee and video all load fine, but the boxart do not show.
Also this is actually an arcade cabinet with joysticks/spinners and a trackball, but none of those works. Only the USB keyboard works now.
I'm ready to dig into the code and insert some print statements to see what went wrong. Could you give me some pointers as to where to look for these issues?