I am having a similar problem.
My game will be wrapped up with android-crosswalk. I have filled in all required launch icon and splash screen formats.
After exporting, the apk file does show my submitted launch icon. Same goes for during the installation.
However, the launch icon that has been created for my game after installing, it shows the default Cordova icon.
How can that be changed?
Note: I have wrapped up the game signed by intel xdk and installed the created apk directly on my phone. Playstore wasn't involved in this process.