Keep up the good work. Looks like you are doing exactly everything I've done to my mustang. I was able to sneak in a slot loading DVD/CD burner right under my 7 inch. Nice to have access to a CD rom like an OEM unit.
One thing I ran into which I see you have the same issue is the bondo breaking. Bondo is not supposed to be used to join and fill in two different edges. It only works with smoothing out bumps and uneven surfaces. You will need to use something else to join console and monitor case together like epoxy or resin. I finally got it right on my 3rd version. 1st version I took the monitor out and it stopped working and the new monitor didn’t fit the old case. Version 2 I used a head shroud so I don’t have to open the case and I used bondo like you did. Looked good for the first 2-3 months then it started to show crevices and cracks where the two joined. 3rd version I removed the bond and used epoxy that can handle the expanding and contracting and only moderately used bondo to flatten out the surface. Hope that helps.