On races:
I would add a demon race.
White: Good demons who trade (very) precious items with you.
Grey: Neutral in nearly every aspect.
Black: See them as the orcs in your mod, they attack soon, and with many once they notice your fort standing, they will know no fear, no danger and will spring as much traps as possible before finally dying. High damblock and gore attacks.
They will not use weapons, they will, however (should toady have implemented it) have a variety of poisons. (Paralyse, illness, near-instant death) The leaders will have poisons that can kill a dwarf with a scratch.
The names are just quickly put up and might need some adaption.
A zerg rush race would also be great
just wait till you have hundreds of critters running at you and your traps, you'll never get enough traps up beforehand.
Hyrilleans: as stated above, the 'zerg' race. very fast, very weak, but extreme birthrate and numbers. they will attack with 10 times the amount of dwarves!
Some of the stronger ones hold minor poisons to near-permanent paralyse poisons.