Yes, in 'echo 3 true story', 'echo 3' is likely related to the 'true story'. It could be the name or identifier for the events that make up the true story.
In some cases, a link can boost a story. It depends on where the link leads and how relevant it is. For example, if it takes readers to additional information or a popular platform, it can enhance the story's impact.
In most comic versions, Echo isn't deaf. However, there might be alternate or special story arcs where this could potentially be a trait, but it's not a common characteristic.