Ok, went out and got the little flat and brought it inside to examine it. It appears the color difference is from... um, well... ok, it's from letting them get a little dry.
Apparently they don't do so well when they dry out too much at this young age. But some of them have 3 or more real leaves. Some are still just cotyledons.
I did order a packet of seeds from T&M, I can hardly wait to plant them. Just haven't had time yet. Also ordered a pkt of sedum seeds. Jackie said she got a lot of nice reds in her T&M seeds.
I'm just spread a little too thin to be a good plant mommy right now to plants with special needs. You got to be hardy to survive around here right now (people included)!