If the patents are to be valid they must teach someone skilled in the art how to make them work. If the patents are to be valid or if the IP was to be truly transferred as required by the agreement, there should be no need to contact the inventor.
The license specified the IP to be transferred. Most of the list involved know-how or trade secrets rather than patents. My initial read was that the provision was drafted to basically require Rossi to hand over instructions, but not background research, not information on past failures, not anything on why the device worked, etc. (But there was a provision about hiring Rossi as chief scientist.)
That's relevant, I think, because it does lend a very limited amount of weight to the argument that IH's failures may have been due to failing to exactly follow the directions.