I could be persuaded to shadow blend. Anyone else?
Any other abilities? Some form of pack tactics/swarmfighting, keen scent for blood in the air, etc.?
I prefer the racial bonus to Hide when in shadows approach over a "shadow blend lite".
Can't think of any SA/SQs to add, they don't need any vulnerability to exorcism since it's already covered by their Extraplanar subtype.
So, shall we move on to skills and feats?
The SRD ghoul/ghast skill picks look a good start -
Balance, Climb, Hide, Jump, Move Silently, Spot.
Maybe drop Balance, since it's got fewer skill points to play with, and add Search, since it's got a racial bonus in it, then put 2 points in Search and 6 in each of the other skills?
Climb
6, Hide
6, Jump
6, Move Silently
6, Search
2, Spot
6.
As for feats, maybe Weapon Focus (bite) and Lightning Reflexes?