No, Silverlight doesn't run on IE10 Metro. I just tested that it doesn't run on an arbitrary site, and I don't think it's possible to even whitelist it.
Silverlight can enforce protected streams to the output devices. I couldn't play netflix streaming movies on my old monitor since it didn't support HDCP.
No, they had to kill it because the iPad wouldn't run browser plugins. They then transitioned to a plugin free HTML5 mobile web to help all developers.