1) GIMP, also take a look at "AutoTrace
- converts bitmap to vector graphics."
"CinePaint is image retouching software with features similar to GIMP or Photoshop. However, two significant enhancements set CinePaint apart. It handles 16-bit per channel color (48-bit RGB) and has a sequence manager that facilitates moving through numbered images. That makes it very useful for manipulating scanned 35mm film. It was used in the production of Harry Potter, Scooby-Doo, Stuart Little, and other feature films. It is the most popular open source tool in the motion picture industry."
2) Not sure. Check The table of equivalents / replacements / analogs of Windows software in Linux.
3) "Blender, the open source software for 3D modeling, animation, rendering, post-production, interactive creation and playback (see the features and screenshots). Available for Windows, Linux, Irix, Sun Solaris, FreeBSD or Mac OS X under the GNU Public License."
5) "Scribus brings award-winning professional DTP to Linux and *nix desktops with a combination of "press-ready" output and new approaches to page layout."