What you have are a collection of pre 1966 legal big firecrackers with more than 50mg of flash powder in them so they are now considered explosives controlled by the ATF or more completely the BATF&E ( Bureau of Alcohol, Firearms, Tobacco and Explosives). These same devices were outlawed in my country in 1970. By the book these require an explosives license in the USA to have them in your possession. I have seen a collection like this in the at a fireworks dealer in Wisconsin probably 25 years ago. The fireworks dealer was licensed for explosives as he was a seller of 1.3G fireworks. There is a community of fireworks and specifically firecracker collectors. I am not aware of any exception allowed for collections of this type of antique fireworks. I would first make contact with the firecracker collector community to find if there is any exception to the law for collections like this. So unless you are licensed or there is an exception for this type of collection from the BATF&E you are in possession of Explosives without a license. At the very least considering you acquired these illegal firecrackers without knowing their legal status I would think the BATF&E would likely approve of you transferring the ownership of them to a licensed 1.3G display fireworks importer or dealer.