plastic vases in the shape of helmeted warriors?

[Giannis K. Hoplite]

Unfortunately I don't have any idea about it. Foot shaped ones always wear sandals, which could be a link to Hermes Psychopombos, who guides the souls to the afterlife, but never has it happened that one of these sandals were winged, and Hermes has other stronger symbols, although he isn't always shown with winged sandals.
There are also many arybaloi in the form of Harpies, with bird's body and woman's head, so possibly used as apotropaic symbols.
One cannot rule out however that the helmeted arybaloi were used by soldiers just because they were beautiful and martial.
Khaire
Giannis