Two sisters.

My question is: will there be multiple endings?
Will jokes be added, and will it be possible to dig for Graals?

I don't see the point in making multiple endings, if that's what you mean. The final video will be added. Some humor should be present in the map, but not too much, as the map is still on a serious theme, if I may say so.
I don't see the need to place the Tear of Ashi on the map yet.