Im not sure if it would all fit in the lower compartment, but this might be a simpler way to go about it:
here is the back of the display showing the 24-pin ribbon
and here is an 9.5 inch display ribbon extension cable
(link) that should get me from the flip-head unit (Activities Unit) down to the lower compartment
And I have been seeing little control boards like this one
(link) while Ive been trying to find out more about what components i will need. it looks like it will accept the 24-pin ribbon from the display and just straight-up adapt it to HDMI, but im not sure if this one is actually HDMI out, not in
With HDMI now as the input to the display screen, I could just buy one of these cheap little media players
(link)
It has an IR jack to connect an external IR receiver
(link), and i think i can give it bluetooth with one of these transmitters plugged into that AV port
(link)
Im sorry if over-sharing my thoughts about adding video playback to the trike is annoying anyone, but its nice to be able to throw my ideas and discoveries here. Maybe this isnt the place for it and I should start a new thread?