yes they do yes they do
yes! There is no difference between "Models" of Xbox 360. it is the same hardware, same software, same functionality.
PS3 games are DVDs and do not work on the Xbox 360 consoles regardless of the model type
the xbox 360 arcade can play the same games as the normal xbox 360
yes
No you cannot play DVDs on the Xbox Kinect although you can play them on the Xbox itself.
Yes!
Yes. If you somehow manage to get the Xbox Arcade compilation disk, you will be ale to play their demos. If you have Xbox Live then you can download the demos or even the full game that the arcade has plus more!
no
Not sure about the original xbox.But the Xbox 360 can
Yes, there is a list of games that you can play on it.
Yes it can you.
Yes. There is no difference.