Did you modify any of these? Perhaps to get them to compile. I've used vfdlib myself and it worked like a charm.

Also, from looking at helloworld.c, it doesn't have a loop so it should just bind to the hijack menu and when selected run for 60 seconds and exit. No rebinding or anything. It could be that hijack doesn't play that nicely with multiple applications bound at the same time. Just try with only helloworld, you should be able to start it from the bash prompt.

As far as documentation for the ioctls. I just looked at the hijack.h header file and the sources. You can also look at how other applications are using hijack.