The mic on the head unit works fine. Just in case you didn't know.
Check out this post regarding the rear cam:
forum.ih8mud.com
You can buy a single DIN DVD player and use the HDMI input or the RCA.
I wonder if you can use the factory DVD player. I haven't looked into it.
Check out this post regarding the rear cam:
LC & LX470 Tesla Style Screen Radio Upgrade with Climate Control: General Discussions
Do your A/C controls work properly? Did you do something special for them to work? I have not been able to put mine to work properly. Any help will be appreciated! Thank You! Yes the air conditioning works. People are having issues with the 1998-2002 non-nav air conditioning, so I can only...

You can buy a single DIN DVD player and use the HDMI input or the RCA.
I wonder if you can use the factory DVD player. I haven't looked into it.