I have tried everything based on this documentation. I cannot get rid of the default phone gap icons.

cordova.apache.org/docs/en/5.0.0/config_ref_images.md.html

Can we please get a tutorial on how we can accomplish this with Cordova Builder?

Solved. I simply used xCode to find out where the default icons and splash screens were stored since I am only doing iOS for now. Simply used a great little iOS assets generator to generate all my icons and splash screens in seconds and replaced the default ones with the new ones. Works like a charm.