Hey, for the first Questions i got no answers
Everytime i got to Cromwell, he was there ..
And i dont know how to locate Items you sold, but for the "crazy" Sword, you should try to get Anomen in your group. He´s a powerfull NPC with a nice story and the sword is one of the best you can find. In ToB i think you can improve it to an Avenger + 6. But dont count on it
Hope i can help you
Warlock762