1) The special ability is changed separately, and the icon with the description is changed separately. I assume you only changed the first one.
2) It needs to be disabled with a script. SetObjectEnabled(script name in quotes, nil); Something like that.
3) The hero was probably in the database... Reserved. Check either in the manual or on the same map. I used hero reservation in "Adept of War."
1) Ideally, this specialty should have appeared in the hero's settings. For example, I changed Ilia's specialty to increase the number of harpies. In her settings, it shows "Dark Mystic." I read the topic, found something about the specialty, but, as it seems, it's not the right thing.
2) Thank you.
3) And how do I check it in the map itself? I still won't understand anything in the manual.
And one last question... Do you happen to know exactly how much experience is needed to reach level 40?