Current questions and answers regarding the map editor.

No, unfortunately, it is not possible.

Is it possible to calculate the balance of a battle in some way?

In theory, it is possible. Each creature has a Power property (you can view it in the xdb file data.pak/GameMechanics/Creature/Creatures/etc.). If I understand correctly, they are summed up for each army, multiplied by a certain coefficient corresponding to the hero's strength, and then the size of their ratio is checked.