Playing catch up a bit so bear with me…
Leto’s symbols are not very clear cut, but she does have some distinctive symbolism associated with her on closer observation, even if it is subtle.
The high crown: As is distinctive of powerful goddesses of authority (Rhea, Hera, Demeter, Persephone, some depictions of Aphrodite, etc) Leto likewise wears this crown establishing her as an authoritative queen goddess in her own right. It represents the power and authority of the goddess.
The veil: Distinctive to Leto is the large full covering veil that the goddess often wears to conceal herself within announcing the goddess as ultimately unknowable to men and possessing the most hidden and obscure of things within her domain.
The spiral “vine” staff: Bearing a staff that resembles vine shoots with its tight double spirals, this staff held by Leto may associate her with underworld by its design and/or agriculture possibly as a goddess who encourages tender sprouts to rise, maybe even particularly among vine plants such as beans, or perhaps even grapes given Apollons association with aiding in preservation and harvest of the vineyard. Yet given the Pharaohs as a late autumn thanksgiving to the lord in Hyperboreia there is a strobg chance she holds a bean stalk in her hand. Especially given the association between beans and the dead.
Of course she has numerous animals associated with her domain’ transitory and typically chthonic transitions:
Animals: crane, wolf, frog, serpent, honeybee/hive, shrew.