Well, looking this description of the document dump made by the FBI, the most important question has not been answered: how did he weaponize the spores.
Drying the spores with the lyophilizer is certainly possible, but this stuff was weaponized in a sophisticated way. It was reduced to tiny particles with a coating to prevent them from clumping, and it also gave them a static charge to help create an aerosol.
This is a non trivial operation, and the equipment, and expertise, was simply not available at Fort Detrick.
If he was acting alone, then we do not have the means made public yet.
I’m about 51% on this guy being the mailer, but more information needs to be released.