You can add any information you want. There's a predefined set of fields like start time, shot number, description but you can create your own fields and select the field type (i.e. multi select, checkbox, text input) and change the order of the table columns.
Shot lists and storyboards use the same information in WhoCan. A storyboard is using the same shots but displays them with a large image in a storyboard style. You can easily build a shot list and storyboard without doing any work twice.
Yes, you can export shot lists and storyboards as PDF.
Yes you can duplicate previous projects and keep any existing shot list configuration for your next project.