Hi there bakubaku!
I can't unfortunately answer to all Your questions, but I will to a few of 'em!
"Respawn" in most PC games means that a "dead" unit is brought back to life. Normaly at another location than where the unit was killed.
To add a command in the action menu are several ways. Here's an example:
You have a street lamp and want to turn it on, place the street lamp in the editor and type in its "Init" field:
This addaction ["Turn Light On", "LightOnScript.sqs"]
About the game Logic, you should try and get a tutorial for it. I know one can do lots of different things with it. It can be real useful to one who can use it. (Sorry, I don't much)
I have the comref here so if You don't have it and want it, let me know, I'll post it here.