2-4
Yes you can still save your games as long as you have the memory card inserted.
Yes, you can play regular xbox 360 games on an arcade unit. The difference in between the arcade unit and the pro system is the pro system comes with a hard drive to save game data/videos/etc.
The Xbox Arcade is an Xbox 360 and it comes without a hard drive. What you are calling an Xbox 360 I'm assuming comes with a hard drive and if you are thinking of buying an Xbox I recommend not buying the arcade as you cannot save games without a hard drive.
the xbox 360 arcade can play the same games as the normal xbox 360
Zero, only the Arcade unit has internal storage built in. Otherwise you need an HDD to save games.
To download arcade games you need xbox live, but all you need is a silver membership which is free.
Currently there are no Kinect-enabled games on XBOX Live Arcade, but games using it have been announced.
The Arcade console supports all xbox 360 games.
Yes, there is a list of games that you can play on it.
I'm not sure but i don't think so
If you have an Xbox 360 Arcade i don't think it can read old xbox games.
About two differences: one: the xbox three sixty has a harddrive two: the xbox arcade comes with free arcade games but doesnt have a hard drive