One thing is very unclear to me: Does having multiple peasant huts affect the rate at which new peasants spawn, or will it be the same rate whether I have one or a hundred huts? I know the speed is tied to your population--it's faster when you have 1 peasant as opposed to when you have a dozen--but is the number of peasant huts a modifier too, or does that just affect where they spawn?
No. The amount of peasant huts dosn't affect the populating rate.
But there are still some option what can you do with multiple huts. First of all, it is more than important if the water is far away from the rice. Other than this, you can use it to build larger base since you can set which hut spawns peasants. The AI often use this strategy to slow down the siege. Oh, and it is always a fine trick. Build some huts away from base, make illusions about your actual location. (Sadly the AI know where you are, but human players can be tricked XD )