I've been trying different combinations - my latest is all 14 yr olds - 2 male and 3 female. I set one to farming and the rest to research. As soon as they amass 5000 tech points, I purchase construction and put all five to work on clearing the rubble from the fire pit. Once the fire pit is in working order, I assign one of the peeps to be a builder on the love shack, one to be a farmer (not necessarily the original farmer), and the rest as researchers. I like to get them all Adept at all the skills so that I have plenty to choose from after the shool is built. So far, so good.