The gist of it is that I took code inspiration from https://toji.github.io/texture-tester/ and instead of calling texImage2D
I called compressedTexImage2D
with the PVR's array buffer that is loaded in the cache, but it's not quite as simple as that (you have to take other factors into account like the compressed texture format, ex.: ASTC/S3TC/etc.)
We plan on creating a push to the Phaser run time so it can help others, so maybe I will post the link to that here so that it can help others.