A couple bugs were fixed, that's all really. It sounds like they weren't captured but merely died/went missing. Character's will only get captured if their health drops below 0 during an Expedition. I might change that in a future update so there's a chance if they die while Exploring that they'll be captured instead.
Haha yeah, it's a little vague at the moment. I plan to add more of the Event Book Descriptions (at the start of a time period) to explain what happened when it can't be displayed in a character's journal, like characters going missing/dying.
Absolutely I can add labels to the expedition items, that's a good idea :)