What are your thoughts on Keen Intellect for those who aren't of those clans mentioned? Potential for refluffing?
Refluff as necessary. Something to do with familial tendencies.
Lovely feat crunch time. I looked at the averages for CR 8 monsters at http://www.minmaxboards.com/index.php?topic=3472.0 and found they're around 96 HP with a max of 180. This has me wondering whether it'd even be worth it to take Mortalbane since my character won't be able to contribute much to actual damage. Weapon Focus or Point Blank shot for accuracy, maybe. Definitely Ability Focus: Eldritch Blast though since saves are going to be a hassle when we start.
Since you seem to be putting this out there for other peoples 2cp:
Weapon Focus probably won't help much, since it's just a +5% chance against their touch AC. And you should be able to hit most things Touch AC pretty reliably I would think, you're already at +6 I think.
Point Blank has two issues: it isn't much of a boost either; it requires your squishier character to be closer to the action. You don't want to be in the same area as the fighter-types when a Gorgon uses it's breath weapon, do you?
(Note, as a DM I generally consider SoD's from my side of the screen to be unsporting, Gorgon was just an example)
Between the two, I'd go with WF though.
And I don't think Mortalbane is all that bad though. It'll average +7 damage per use, for 5 uses per day. In a battle for your life, it is best to not underestimate the importance of a couple of extra damage per turn. If the party were facing whatever it is that has 180HP at CR8 (too lazy to look up), then the battle would likely last 5+ rounds. A battle wherein you'd know from the outset that creature was a tough one. So you'd have used all your Bane uses ASAP in order to try to get that battle over with while suffering as little damage from the enemy as possible. And across 5 uses, you'd average an extra 35 damage. Which isn't bad in the long run. Though the main problem with that feat is knowing when to pace yourself, and when to go all out.