I've heard that Superman is the descendant of Rao, and by extension would technically be a Kryptonian demigod, but I've not heard that he's a fallen angel.
Your list, in relation to your question, is a bit on the broken side, but I'll see if I can "interpret"...
Lucifer, as presented, is the most "mystical" of those listed, and comparatively the most potentially influential, contextually. -- 200+
Phantom Stranger, being an angel in the "since before time/I actually remember crap from Pre-Crisis" sense. -- 150% (though this doesn't apply in combat terms)
Cronus with the Godwave - the proto-generation of power for the Greek gods (and by proxy, Darkseid, himself, and much of the power that helped form reality). 145%
Zeus, though as with many of the gods as they are now, isn't what he was in his "heyday"; over the past 25 years in comics, his power has waxed and waned considerably. 85-125%
Hades, Poseidon, Athena and Ares are approximately equal, more or less, with Ares' and Athena's current states being major plot complications in this equation: 80-115%, depending on time and place.
Shazam/Lord Marvel, wielding godly power and wisdom of both the past and future, but still bound within the causality of the universe (much as Darkseid is, to his annoyance) - 100% (being essentially equal in mystical power to Darkseid's cosmic power, but without DS's periodic jobbing aura).
Captain Marvel/Green Lantern (Alan Scott, presumably); Billy has a greater "core" of mystical power, while Alan has a greater *application* of mystical power. Both at about 50% or so, with occasionally higher and lower showings...
Superman: Assuming you are taking him in a conceptual context -- as a demi-god of Krypton/Ny'l'uyl, or a descended angel/Nephilem-- then we're talking around 25-50%, depending on available power; otherwise, 0%.
The numbers I used were all relative: I'm not scaling this in any literal sense, as it would just be absurd, given the powers demonstrated and relative limitations/plot complications of various characters. Hope it helps/makes sense, and it needs stressing: this doesn't indicate who might win a battle, as such, against someone else on the list, but rather their relative measure of mystical essence/standing.
__________________ Why am I here commenting on this crap?