1. Yes you are right..This is the displacement in the hot condition. In your case, after pulling the pin the system does not produce net load or your piping system is not flexible enough to displace the system. Since the system did not displaced at hanger location therefore the spring did not experience extension or compression from its theoretical cold load setting.
2. I'm not sure what specific report to show the weight of the system without its content. But I think you can use restraint report. May I ask you, What do you after this report? and what is the significance of this report in relation to your analysis?
3. As Explained by Sir Dave Diehl.