Just to clarify your question, you are allowed to have more than one Lost Soul with a Special Ability, as long as the Lost Soul cards are different. In fact, all of your Lost Soul cards can have Special Abilities. However, as Redoubter stated, you can only have one of each specific Lost Soul in your deck per 50 cards. The Starter Decks were just printed with only one of the Lost Souls having a Special Ability per deck so that new players knew they existed. :-)
