In completing steps 1-5 of the Iowa Legislative History process, you will have likely found most of what will be influential to the courts in determining intent. It is possible, however, that by continuing the process you might find something relevant for your particular piece of legislation or obtain additional useful background or other contextual information.
Committee minutes are available, but they tend to be very limited in their coverage. They note who attended a meeting and what bills were voted on/discussed. They might mention if someone spoke or distributed materials to committee members. These are becoming available on the Web site, via the Committee Directory link below, and can also be accessed by contacting the Secretary of the Senate or Chief Clerk of the House.