Just want to quell some fears here, but at the same time, I can't talk about some of these aspects in detail. However, the archives belonged to George Lucas, personally and did not go to Disney with the sale of Lucasfilm. However, George has now turned them over to be managed by a third party and the archives are now on a very hard lockdown due to legal mumbo-jumbo.
Will it always stay that way? I certainly can't say. However, when Lucas owned Lucasfilm, there was a vested interest in using the archives to help licensees make great products like the Fett helmet because at the end of the day, it means more money for the licensee and ultimately more money for Lucas. Now that the direct tie between Lucasfilm and the archives has been severed, there is no strong motivating reason for the archives to work with what is essentially Disney licensees. Give the recent change in attitude, by the archives, toward licensees, it does not bode well for the future of having the kind of access that brought you the Vader, and will soon bring you the scout and Fett...