Sloth = Idoru/ Idle (Can't believe it took me this long to figure this out)
Lust = Luslia. Pretty obvious
Gluttony = Gruz/Glut-ring?
Wrath(?) = Furi/Fury-anga. Considering Idoru's anger management issue I can't imagine this guy.
Also kudos to author for using sirens instead of the overused harpies. Avian sirens at that, not the water variant that is assimilated into mermaids (another overused species)