You get builders whenever the parents had the skill. That doesn't really depend on puzzels. Some of the kids born look like they have no skills but if you looked inside the game file they are there. It takes a certain numbers of "points " in a skill before it shows up in the skill bar. I was quite surprised that they really do get some points in all the skills the parents had high numbers in. This is why some look like they gained skills faster then others, they had almost enough to show up. I have many villagers on their own that will forage or harvest depending on their skill or likes. Personally I would rather they leave the berry bush alone after farm 2. I do wish that that farmers wouldn't run off fishing during harvest time. The AI is pretty good but could be better. The lure to puzzel objects is a bit to high. It helps first time players but after awhile it's just annoying to keep them on task. Pathing could also need adjusting. I notice it far more with the villagers that like running. I would love to see a better way to heal people then throwing them at the food bin, sometimes as many as 15 times. But all in all they did a pretty good job.