I checked out both recruitment systems and they only seem to be recruitable from Mongolian hordes but whenever I come by them it says I have bad relation with the owner of the horde. I cheated to get my relation up with said lords and it still didn't let me recruit them. Being in the same faction as them also doesn't work. They seem to have the highest level horse archers along with Cumans so if there are alternative 30 level horse archers I'm open to that too but main thing is the Mongolians.