No idea about the first one, I'm not sure. I think the protection field would move but I'm not 100% sure.Ahh ok.
Second sometimes you have to pour water quickly(not to drown them) over them for their "blocks" to update, before thy can breed again :P
For your PS I have no clue never heard of that but for your villagers in a 2*2 area our population control only allows 2 entities so in a 4*4 area if math is correct your only going to have 8 entities or less if they all huddle in one corner then it will only count the 2*2 area.... I have a sheep farm it is about 20*20 I had tones of sheep but if I huddle them in a corner they end up dieing after about 10 minErr...I meant I had 8 4*4 areas, all combined so it is a huge area.
Hope that helps