These are nice looking small craft for rowing and sailing.
Looks like your questions should be directed to the builder. The 12 footer shows a 'displacement' of 135lbs. I suspect that this is the weight of the boat. I would ask the builder the true 'displacement' or how much weight can each carry besides the weight of the boat. If it looks like the 12 footer will carry the family, just be sure you have them all onboard when you beach and want to lift the boat above the tide line.
