How does teamwork play into voidstar? I feel that warzone is less about teamwork and more about speed/quickly burning through your opponents.
EDIT I just watched the voidstar walkthrough link you provided, which helped (though most of it was common sense).
Those videos are for preliminary viewers who want to know the basics. To answer your question though, its not always about how fast you can burn your opponents, especially when attacking the bridges, because if you kill them at the bridge, they're all there waiting for you when you finally get the bridge open.
Voidstar is all about discipline and learning how to distract/stall enemy forces. Rule #1 of Voidstar: NEVER CHASE KILLS! and STAY BY THE DOORS! I can't tell you how many times I've lost/won a voidstar because the people defending the doors run away just for that 1-2 seconds to finish a kill. Often I will trick an enemy into chasing me away from the door so my cloaked teammate can sneak in there and set the bomb behind their back.
When a door blows, and you're racing to attack the next node, make sure you have someone who is a designated "hallway fighter" and by this I mean, someone who's sole job is to distract 1-3 people for a number of seconds to give your teammates ahead of you time to get to the next node with a reduced number of enemies to oppose them. Your enemies think they're getting a free kill, but what they're really doing is wasting 2-6 seconds gang-banging captain decoy while you activate the bridge or drop a force-field.