With regard to mob spawning, a 17 chunk by 17 chunk area centered around the player will have a passive mob cap of 11, meaning that if there are 11 or more passive mobs (i.e. animals) in that area, no new passive mobs will spawn. Villagers do appear under the passive mob list, but they have very different spawning behavior than animals do (i.e. they will not randomly spawn, and can only be created either at world generation, through villager breeding, or by curing zombie villagers).
So, for the purpose of animal spawning, are Villagers counted towards the passive mob total? In other words, if I had nothing except 11 Villagers in an area, would no animals spawn at all there?