For myself, I'm still waiting a pick in the fort I start (never dig channel in a 3*3 square with no ledge to dig, opening in an aquifer, in the middle of winter :p, with your only miner) and cutting wood like crazy. So, I'm pretty far to go underground. I think a lot of people most focus on getting the tech tree underway and killing some of the nasty stuff up there.
Not going down, down, down and killing everything in sight Nevermind.
The meowkin are cool imo. I have read that you have some trouble to getting them being at the right place (too much powerful for what they should be). One idea would be to create special, small weapon, that they can only use. Such small weapon could be made not really effective. I remember a mod that focus mostly on creating a cat race (Catsplosion), the number were ridiculous, on any given period of time, the world contained 10k of this race. They would beat up the crap of elf, but they were no match to iron/steel dwarf. That exactly what the creator did, giving small, innefective weapon (Xbow replace by blowgun as an example :p). If they breed like crazy, survival shouldn't be a problem in worldgen.
Otherwise, you could put in lore that in fact they are pretty powerful as a civilization, but underestimate by the other because of their fashion (effeminate cloth for male, small size, etc.). Knowing that in small band they are weak, that should do the trick, one way or the other.
1 question, is it DF vanilla or something my side not correct, my dog don't stop fighting, so much I had to put them in a pit to avoid they kill my hen. Ha also, meokin are crazy, they pillaged 35 times a gobo town before destroying it, 25 times in the same wars :p