There is speculation among some occultists that certain demons (generally spirits) from the Ars Goetia who are energetically connected to Hecate. There is Murmur, Orobas, Naberius (Cerberus) and spirits connected to Qliphothic tunnels like Gargophias. I also heard Surgat is under Hecate as well.
I would like to ask what other infernal spirits are directly subservient to her. Like a list you’ve been able to compile over time from experience?
Most of Greek Daemons (and I mean a really amount of them) serves Hekate. I can go as far to say that even Angels and other divine or deities can be “constrained” or have some respect towards her, one of her epithets are “Mother of Angels” and “Queen of Daemons”. I recommend the book of Hecate Apuliensis about Hecatean Magick, there you will find 72 Daemons (that are not the same Daemons from Goetia) that can be work using the authority of Hekate.
That’s your opinion, it’s not a fact. I’m talking this because I do have knowledge that you can use it, it’s not something that I would advise but with people that do not have too much connection or synergy with the angels it’s a way to work. Again, one of her epithets is “Mother of Angels” I will leave for that
Edit: By the way, Hekate is a Titan. Some of her myths said that she’s older than most of the gods (some myths say that she was born not so long after the Great Primordials: Caos, Eros, Érebo, Nix…) and she’s the personification of Magick. Of course they’re multiple deities that are also “magick personification” like Simbi from Vodou, again I’m not saying that every god obeys her but that her names/epithets can be used to constrain some of them… Just like Yahweh that in my interpretation is a false god can still be used to constrain some folks because he’s an old god of War and Thunder.
I’m not sure if they are considered Infernal but in Jason Miller’s Hecate course after summoning Hecate there are several triads that can be called upon for different purposes including but not limited to: The Graces, The Fates, Gorgons, Graeae, Furies, Sirens, and Harpies. I’m sure they can be worked with without first calling upon Hecate but in his system she is basically their overseer in the ritual.
Historically there are no connection between Hecate and the spirits you mentionned.
They come from two different systems. I mean unless you find a direct link between them, maybe you can try to put those spirits under the autority of Hecate.
They only link i see is the “fallen angel” from The Testament of Solomon named Enepsigos