What did you mean by 1_? I have "Fullscreen in browser" set to "Scale outer".
I meant about this option. I normally uso "Letterbox Scale" to keep the ratio.
2_ So I just add a third-party plugin to XDK, with ID cordova-plugin-screenorientation-portrait and source https://github.com/cranberrygame/cordova-plugin-screenorientation-portrait?
You'll need to install this plugin in C2 and insert it in your project (if you haven't done)
4_ Which final app?
After your build it using the Intel XDK