Regarding Miracast, this too was recently shown to some of us in the media at a private event in New York City. As noted by Belfiore, the hardware used are simple engineering samples, much like he showed in a photo on Twitter today (see below). These devices look like normal Lumias, but their updated Qualcomm chipsets can handle the dual display output needed for Continuum.
 
The Miracast demo I saw was just that: the phone connected up to a TV and wirelessly beamed a second screen. Universal Windows apps (UWA) like Outlook were demoed with Continuum specifically displaying how the phone app can scale up to a full display for a computer or TV