This is beyond my capabilities to attribute, However, I think the bust type may give us a few clues and narrow the field some. I'm think the bust type was used for only three or maybe four of those you listed. The three would be Germanicus, Claudius, and Nero. The fourth I would add if these three don't prove out would be Augustus, but only as a last resort IMHO.
Personally, I think I would concentrate on Claudius and Nero.
JW
Personally, I think I would concentrate on Claudius and Nero.
JW
























