Knowledgeable (Ex): A faerie phiz makes Knowledge checks for any Knowledge skills as if it had a minimum of 10 ranks in that skill. To surpass the 10-rank minimum, it must assign more than 10 ranks to the skill as normal.
Agreed to knowledgable and to an unearthly grace-type ability. Considering their affinity for force effects, giving them mage armor wouldn't be much of a stretch.
The original has Int 17-20, so that seems to be a bit of an inflation. I'd drop the mental stats by 2 apiece, and likely swapped Int and Wis around since these seem more of a "wise sage" trope than a "cunning savant".
The Constitution also seems rather high. I'm not seeing anything in the description that indicates they're super-robust, although the 5+5 HD suggests better than average Con, so would cut it down a bit.
So, I prefer Str 11, Dex 15, Con 16, Int 18, Wis 20, Cha 17
I agree with Outsider, since they're native to the astral plane and have all those magical powers. I suspect they were once Humanoid (Extraplanar), but that was long ago.
I was about to wonder about their relationship to the githyanki before I came to the very bottom of the article. Outsider for me as well. I'm surprised they don't view the 'yanki as pesky interlopers. I was wondering about the Con 20 too.