Help with legatus legionis impression

[Carlton Bach]

And how are scenes and symbols from mythology specifically linked to one person?

It does appear that certain emperors developerd and used certain iconographic programmes for themselves and repeated them on their public art, actually. This isn't exactly my field, but given how archeology is still strongly influenced by art history, I had to do the basics back when. Frex, the Italian Tellus is very much an Augustan (and to a lesser extent later Julio-Claudian) thing. IIRC it was Claudius who used the river god Tiber a lot and Tiberius has scorpions. You can find details of this (IMO highly speculative) system in every good textbook on imperial art. It strill leaves a lot of mythology generic (everyone does thunderbolts, e.g.), but some combinations are indeed fairly specific.