It wasn't a "Congressional report," except insofar as it was a report issued by a Congressman. The Congressman in question, Mark Souder, is on record in support of "teaching the controversy"--he writes on his Web site,
But why can’t high school students just learn the standard scientific view and be done with it? Science is science, and that should end the debate.Souder commissioned the report to be written by his staff, but it wasn't accepted into the Congressional Record and was only published in his capacity as an individual representative.Normally it would. But evolution is different.
Similarly, as far as I can tell, the "OSC report" is one letter written by one attorney summarizing his preliminary investigation. I can't find out much about the lawyer except that it's been claimed that he had no prior employment law experience before his appointment to the OSC.
All that you say may be true. It is still an analysis of the event. There would have been no way to get the actual email traffic out to the world without those two reports.(I don’t think that the Smithsonian itself would have released them even if it had the power to do so)