Yay, warlocks!
I think this is a well thought out and logical approach. I’m no expert by any means, but I’ve put a lot of time and effort into this character, so maybe I can offer some helpful points.
One thing I enjoy doing for my characters (of all classes) is look at their profession/calling/life choices through the lens of their race.
Iantha here was a mage living in Dalaran, once upon a time. For her, that was quite a different experience (compared to other mages) since she was a part of Kael’s forces and was jailed by Garithos with many others. Eventually, she followed her prince to Outland which is where her journey to “Warlockdom” really began.
Without going into too much detail, a lot has happened since. She’s a member of the Black Harvest, has had run-ins with the law (specifically blood knights) and remains heavily addicted to magic. Her status as a warlock and as a blood elf has informed much of her story as you can see!
Outside of that, I’d recommend reading lore-related warlock articles, as well as anything you find interesting in the forums here. One in particular is a fan-made book mentioned here: The Harpist's Grimoire (IC Book, now in TRP3) - #11 by Arvinstal-wyrmrest-accord
Sorry for the long post, but hope you find it helpful!