There is no such thing as Init commands, M'kay.
They're just all the very same commands that can be used everywhere; external scripts, activation fields, ...
Init field is just a place where the command will be executed when the mission loads up. ie before it starts.
You can setbehaviour, setpos, setcaptive, inflame, camcreate, createunit, createvehicle, whatever, with init fields.
For easy management of pre loaded commands you can (should) make a sqs file by the name
init.sqs which will act just like the init fields in editor.
Best way for you to learn about init's and commands is to head for the editors depot and get some tutorials and the command reference.
Cheers
edit[size=0.8]oh darn macguba, you already had this covered[/size]