I'm not entirely sure as 'hc visual novel' could be about many things. It might be a story - driven experience with unique characters and various plotlines.
Well, in the world of graphic novels, TP is commonly understood as Trade Paperback. It's a format where several comic issues are compiled together. HC, on the other hand, means Hardcover. These are usually more expensive but offer better protection and presentation.
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.
The Ugly Duckling is very popular. It tells the story of a duckling that is different from the others and is initially ostracized but eventually grows into a beautiful swan.
It's hard to give a definite answer. Different comic universes and storylines handle the inclusion of Echo differently. You might want to check popular comic franchises or search online for more detailed information.
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.