It's my understanding that while Kubrick wasn't crazy about the three short films he did and "Killer's Kiss", he didn't actively try to supress them as he did with "Fear and Desire", which has managed to avoid any non-bootleg release even though it's public domain, which is a testament to the power of the Kubrick Estate.
Back on the original topic, ALiP is a great documentary! have seen in many times from a taped copy and would gladly purchase the second it's released. I already own many of the remastered edition DVDs, so buying the box set just to get the doc would be ridiculous.
The third, The Killing, is considered the director's first truly successful film, and is a taut, gripping heist drama that goes layers below the surface.
"Fear and Desire" and "Killer's Kiss" may be considered short by today's standards, since they both run about 68 minutes, but they were feature-length films when they were released. I see no reason to count either of these films as short films at all. There's a clear difference between the running times Kubrick's first two films and his three short films, so to lump them in the same category would be inappropriate.
After owning the remastered set for a few months - I've discovered that I replay the Life In Pictures more than the films. The set remains the jewel of my collection.