This is not comic con footage. All it is is the Boston demo from E3. The only thing different is Alex's commentary. It never gets old watching it though Probably my favorite demo that they showed. That and the wilderness demo.
Also, he said that assassin's don't always work alone and these are his allies. He never said they were assassin's. They already confirmed that there isn't a brotherhood system, but something similar. i.e. what's show in the demo.