Survey don’t always matches the exploration date and same goes with explorer vs the surveyor team... maybe we could have 2 extra columns to keep track of the explorer teams and dates and a list of explorers, similar to surveyors. Displaying exploration date would be great as well.

As you say, survey date is an essentiel calculation parameter and the exploration history can be treated a simple information and so it can be filled into Info or Comments for sure. But then it becomes meaningless. I believe the exploration history is far from meaningless, and to the opposite, I find it essential. If there is a dedicated field for that, then it does become a data that can be used, displayed, analysed.... Coloring the survey shots base on exploration date could gives you a very interesting output when a cave has been explored for decades. You can also think of the same over an entire karst with many caves and tell the story of it exploration. If you can filter by exploration date, you would be able to produce an animation showing the exploration progression over time for example...