1) Seems as if the author moved away from using spheres aligned with the traced cone (using cubes). I wonder why (better coverage of the cone most likely)
I don't think so. He still uses spheres. He uses the sphere's center (texture coordinates) and radius (mip level) to sample the color/visibility buffers. In the video he is drawing the texels (pink squares) used over the cone (if you pause the video you can actually see the cone behind some of the squares). I'm not sure what the color on the squares mean though... My guess would be that it is the weight based on visibility and trilinear interpolation that he mentions in the article.
2) The cone angle varies!!! Meaning the glossiness term drives the side of the opposite length of the triangle (as opposed to the actual cone angle)?! See as the reflected point gets closer to the character the cone angle widens dramatically. I wonder if I mis-understood the article or if the author is using a different approach in the video...
I don't know about that either. I think that the angle should stay the same (assuming that the glossiness of the ground is constant) as the reflection gets closer to the object and the cone should get smaller.