I would never trow any out, maybe over time, when space becomes important but its always worth a try to safe them, might just be a little humidity problem at the start, the first few days the seedling gets his nutes from the seeds and only need water for roots and a humid enviroment above soil to prevent the leaves getting dried, needing water from a rootsystem that simply isnt there yet, i usually use mixture of coco and gardensoil, and keep anything that captures moist above it. Any dome like feature that can give visualyy condensed environment. So in this case i would chuck those yellow brown leaves off. Keep them in a high humidity and wait for two to tree more nodes and go back to without humidity. Can always use them later for try outs anyways, like manyfolding or so, have fun