That sounds about right, and I think the grig stats you mentioned upthread are a good fit: Str 5, Dex 18, Con 13, Int 10, Wis 13, Cha 14.
That suits me, we'll have to zero the Con stat of course, it being an Undead.
We can modify the Grig's longsword & longbow attacks for the individual version. Not sure how we'll represent a swarm of little undead fey all shooting away with their little longbows, though.
I'm thinking we should aim for the high AC of the Cerilian version. An AD&D AC 0 is around AC20 in 3rd edition terms.
Size +2, Dex +4 leaves it 4 points short - shall we give them natural armour or wee little chainshirts, or a combination of natural and artificial armour?
I remember reading a folktale about clouds of limedust and splinters raining down from the sky from their shields during one of their perpetual wars, so how about Large wooden shields and the same +2 NA as a Grig?
Armour Class: 20 (+2 size, +4 Dex, +2 natural, +2 shield), touch 16, flat 20
It's got some pretty nasty special abilities.
Magical Flight (which it can impart to its zombies)
Create Spawn (slain Humanoids become zombies, do slain Fey become more Sluagh?)
Elfshot (deadly poison arrows)
Domination
I'm also thinking DR/cold iron and turn resistance would be appropriate.
Should it have low-light vision as well as darkvision?