There is an official announcment about this subject a number of times.
It's on Nintendo's developer page regarding html5/Unity.
"The Nintendo Web Framework is a development environment based on WebKit technologies"
The answer is no. WebKit is so far been implemented as a 2D Canvas render. :(
Also and I'm less sure on this, but it's likely that there is no Advanced WebAudio, just the basic audio player. For all we know the WiiU export could be as bad as CocoonJS until further notice :(
If you can find it. Nintendo also provided an image displaying what technologies that there Nintendo Web Framework uses. I however have not been able to find that image.
Since C2 is an JS export C2 can only be a %100 WebFramework game.
I think there should be a top post thread in the forums regarding non PC hardware exports of what they can and can't do.