Yes, there are Succubae and Incubae and in fact one joins Tom’s entourage in book 2. And yes, this demon is a true sex fiend…well…OK…not a fiend as a fiend is a type ii, and this one is a type iii….
Also Lillith is not technically a Succubae, but she’s extremely gorgeous (usually). She is of course, the First Temptress. She took her breakup with Adam as an excuse to play the field, so to speak. Naturally, she has moved on, but do not EVER mention Adam’s second wife, unless you want her to rip every rib from your body….
Demons, as a rule aren’t that interested in sex with humans (other than Succubae and Incubae—the whole raison d’etat of which will be provided in Book 2) for the simple facts that humans are too fragile. They break way too easily.
No, non-humans are about as dumb as humans. Elven wizards in particular. Dwarven wizards are usually a bit brighter, and more likely to be Thaumaturges, the same with the odd gnome wizard (really not a lot of those–they tend to be more “tech” oriented) and Hearthean Wizards.
Similarly The Aetós tend to be more into Enchantment (Air) and The Gleg’ren like Sorcery (Water). The I’iskatha, haven’t got a lot of wizards, but I’m not that sure about them…