Spawning units ingame is not an addon, it's scripting. I'm can't remember offhand how to do this, but it's most definatly possible, with both BIS units and addons.
Take a look at this thread:http://www.ofpec.com/forum/index.php?topic=26158.0
AFAIK, the only way to change a unit tracers is to change it's config (or give it a new config), but i'm not an addon maker, so wouldn't know.
The god mode cheat doesn't work. I don't think it ever has