Speaking of golden frogs:
The Panamanian golden frog is something of a national symbol, appearing on state lottery tickets and in local mythology. When the toad dies, it is thought to turn to gold and to bring good luck to those fortunate enough to see it. In 2010, the Panamanian government passed legislation recognizing August 14 as "National Golden Frog Day". The main celebration event is marked annually by a parade in the streets of El Valle de Anton, and a display of Panamanian golden frogs at the El Valle Amphibian Conservation Center in the El Nispero Zoo, El Valle.
Possible link to Legoretta? This also gives us another location:
I might have found a few leads for The Swallow.
In this Greek tale, a trio of sisters turns into birds to escape death. One of which is a swallow named Procne.
This would tie in with the Argonauts, 787, and Europia.
Second lead: In Egyptian lore, Swallows were associated with the stars and the dead. It is said that the dead could be turned into swallows. But back to stars:
In Spell 1216 of the Pyramid Texts, the pharaoh describes how he has "gone to the great island in the midst of the Field of Offerings on which the swallow gods alight; the swallows are the imperishable stars." The imperishable stars were those near the North Star that never seemed to rise or set, and therefore were "constant".
Ill leave that link here (not much on the page that I didn't say, you could probably find a better resource):