if they are nomads. their methoblasmic activities should be very elastic and their constitution has to be high. even if they are stopping at suitable places, travelling to a different planet alters our body radically. for no changes in our body the traits of the planets should be exactly the same which is impossible. so they might not even know their original state. they are keep changing through time. we can calassify them according to their current state in the last milennia maybe. they should have middle height bodies. thick dry skin. possibly red because of the changing blood pressure. i am assuming they are herbivores since it is easier to sow in space than to breed animals. to be a nomadic race i am assuming they are really good at genetic engineering and cryogenics. if they are we might learn a great deal of knowledge. they should also have strict birth policies because beign nomad means little resources and that means birth control. i believe they make annual census to deaignate exact number and rations. they are probably animal friendly to adapt to the new habitats. maybe they have exotic pets we might use for trade. their family structure i assume mostly matriarchal. they value elders and the women. their joints should be like the insext joints to adapt changing gravity and pressure. they are humanoids i suppose but resemble bugs. space travel makes skin whiter without enough UV. and lets say there is a radiation on the atmosphere where they live. it might happen because no planet is perfect. so they need to hide underground. i am imaginin white bug like hard and white skinned with partially pinky or red soft tissues, thin middle height creatures
