Given how many works of Sci-Fi have made aliens into demons and angels, from the crudely literal to the richly metaphorical. Heck, Arthur C. Clarke made aliens into angels and demons at the same time in
Childhood's End. The idea that people like the Gypsy Angels might be possessed would gain traction. People who are seen as living
Liminal lives, however unfairly, become the focus for myth making. Just look at the actual
Romani people and the garbage thrown on them.
Having watched
Cry of the Werewolf, which had non-Christian worship equated with Satanic witchcraft,
Voodoo equated with Satanism, and an implied Lesbian rape via mind control, in a film that wasn't actually hostile to the Romani (yes I've seen far worse, brutally worse). The simple fact that the
Gypsy Angels have nothing to do with the Romani, and are still called "gypsies" and feared as pirates and Mafiosi, is clearly a reworking of old myths.
The Gypsy Angels are clearly feared and scorned in the setting (and please remember that creating characters that are the targets of bigotry is a way to expose and attack bigotry) makes it likely that paranoids would see them as a possible path for alien influence on humanity.
In the 1970's I remember reading three different UFO contactee books that held that the Romani people were dupes/agents of the aliens. The Gypsy Angels would be even more likely to attract this kind of nastiness.
This might lead to an Anti-Romani defamation league being set up in alliance with
the Anti-Defamation League. Since they'd know the stink of bigotry from bitter experience.