Out of those I'd say 4 looks best, but I don't think it's classic githyanki if that's what you're after.
I'm currently leaning towards hair 29b for my male githyanki PC unless something better comes in August. I think it's one of the ones that was originally limited to male githyanki and it looks pretty authentic to me. (IIRC Voss is hair 30b?). Though of course there's a risk in that case that once we get to the creche we'll find more with the same do, whereas by picking something a bit more out there for gith it's true you're less likely to encounter a doppelganger!
