Hi, yes I'm familiar with the comics.
The first three are indeed Doug Tennapel's work, found on the archived Neverhood website.
The last one looks authentic, might be from his Sketchbook Archives, but I'm not sure.
Old Neverhood site with zip files of the official comics
Doug Tennapel Sketchbook Archives vol.1&2
Currently the only way to play this game on a Mac is to use something like VirtualBox (lets you run Windows inside a "box" on a Mac) to play a Windows copy, because currently no patch has been made to get the game running on Mac. Unfortunately my experience in VirtualBox is limited :/
As for downloads, try one of the top two here.