On the map “School of Sword and Magic (3.2)”.

Please explain a couple of points regarding the game mechanics: 1. On the "Sword and Magic School" map (3.2), the Grail is listed among the available artifacts in the text file, but heroes do not have the "dig" function. How can I make it so that they can dig on this map? 2. On the same map, I noticed that not all heroes from the standard list are available for hire in the tavern (I have an additional mod installed that adds campaign heroes to the hiring list). For example, Axel, who was the starting hero for Haven, did not appear in the list of heroes available for hire after I defeated him. The same goes for Anwen; she simply did not appear among the heroes, even when I intentionally cycled through all the heroes available in the tavern (hiring and firing them). Is there a limit to the heroes that can be hired, and if the number of hero slots on the map is less than the number of available heroes, are some heroes simply excluded by the game when the map is generated, and do they not appear in the tavern at all? Or is there something else going on? 3. Is it possible to add artifacts from campaigns to the list of artifacts generated on maps of this type, for example, "Wings of the Angel" from the Necropolis campaign?