I had trouble using the crosswalk examples as well. You should check out the POC Joe Bowser published here: https://github.com/infil00p/cordova-android/tree/pluggable_webview
note that it is contained in the pluggable_webview branch --edit--
You install the crosswalk browser through PlugMan from this repo: https://github.com/infil00p/cordova-crosswalk-engine
note that the xwalk engine itself is not included in either repo. The plugin repo provides the hooks, the cordova fork provides the functionality to swap webviews.
Joe is a core Cordova team member and created a crosswalk-cordova demo which does work (I've tested it myself).
Lorenzo