back in the 90s if you ordered jazz jackrabbit, all orders included a full-color manual/comic book and a free bonus game. are these also included (comic book as pdf and bonus game) in gog version of jazz jackrabbit collection? and what game was that bonus game exactly? does anyone know?

The GOG version does not include the comic. However, if you look further down on this forum you'll see a post where someone scanned them.

and what was that free bonus game? does anyone know?

That could either be referring to later versions of the Jazz CD-ROM including "Holiday Hare 1994" (which is included in the GOG version) or simply that when you mail ordered direct from Epic Megagames they would typically throw in a disk with a shareware copy of one of their other titles (whatever game they were promoting at the time). Around the time of Jazz's release, it probably would have been Xargon or Jill of the Jungle.