To speak in regards of the Owl, assuming it's a spanish urban legend: the immediate thought that springs into mind is that of La Lechuza.
La Lechuza is a more niche urban legend than that of a lot of other legends featured prior: based in-between Mexico and Texano lore, as a woman who conducted the art of witchcraft and was slain for the conduct. As a precaution: she ensured that when she died, that she would return to the form more associated with her--of a owl like creature that has the face of a human woman.
La Lechuza would be a strange choice among the urban legends depicted, but it might be what they are looking at in consideration to the GSAT success of La Llorona. That they could go further than that of what they have done with the Weeping Woman, and to tell a revenge story based on the urban legend.
A hunter, seeking her prey and to enact revenge of those who wronged her. It might even explain an element Murdy explained of changing the lead character to that of a feminine based sort than that of a male character. Due to the angles that could be taken further than that of say, an El Cucuy (even as they have reimagined him from the previous designs).