All the people and place names in the books are real names. Even Idris and iratze are real words. You can find out their pronunciation by doing this.
Really, it works, I promise. 🙂 The reason I don’t provide a pronunciation guide to the words in the books is that when I was a kid, I used to read all these fantasy books and just make up how the words sounded in my head. Whenever I found out that the author or someone else pronounced the words differently, I’d be really disappointed. If you want to look up the standard pronunciation of the words (which is what is used in the audiobooks) then you can use the above method. But you should also feel free to pronounce them as you like.
The names in my books come from all over the place. Sometimes they can take a long time to develop. Clary Fray is named after two friends of mine. Her name was originally Valerie Frayre (after the artist who designed the runes), then Valerie Frayne, then (when a friend of mine was also writing a book with a heroine named Valerie) Clary Frayne, then Clary Fray (my editor’s choice) — then when I realized Clary was a nickname, she became Clarice, and finally, Clarissa. (She’s not named after me. She is named after my friend Valerie Frayre, and my friend Clary.) Jace was originally named Will, but Jace is a name I always liked, and it needed to be something that could be short for Jonathan (and now the name Will shows up in Clockwork Angel instead). Max and Isabelle are named for my grandparents. Alec’s name was originally Alex, but Alec is a more interesting version of Alexander, I think. Simon and Maia are named after friends of mine, while Maryse, Robert, Jocelyn and others are simply names I picked out of baby name books and the like. (Luke Garroway I picked because it sounded a bit like loup-garou, which is French for werewolf.)
The names of the angels and seraph blades: Ithuriel, Raziel, Israfiel, etc. come from sources of angel mythology. Paradise Lost, the Bible, the Talmud, the Koran, the Enochian magic system, and so forth. They are all, as far as I know, sourceable to specific mythologies. I did not make any of them up, nor did I make up any of the names of the demons, which come from sources of demon mythology like the Lesser Key of Solomon and, of course, the Bible.