NHF – new heroes for Heroes V 3.1.

Good afternoon!

If it's not too much trouble, could you help me understand your mod?

1) Can it be installed on version 3.0?
2) Where can I find a manual with descriptions of the new heroes in the mod?
3) I've edited a standard map of the Land of Outcasts in the map editor. Will the mod affect it?
4) In the mod, the specializations of the old heroes have not been changed, right?

Thank you in advance!