It looks like you may not have good drainage in that plastic container. Could that be an issue? The only issue I've had with seedlings were one pot that had the tops eaten off before it was strong enough to push out more leaves or the ones the squirrels dug up, but I do more them to pots more like the size of your blue one pretty quickly. When I dig up volunteers from the yard, I put 3 or 4 into a pot that size.

Your plants that died back may return. Don't throw them out just yet.

Alright thanks!! I'll move pots for now! Any advice on when I can move outdoors ? Would it be best to wait until after April 30 for danger of frost ?

I would think they would do better in sun and if you get light frost they should still be okay, but you can cover them. We had potss on our driveway when it got into the mby a id 20s. Those protected from the wind and with a blanket over them still had some leaves on them and most came back. Those in the ground that were unprotected also mostly came back -- they are just being a bit slower to get started this year than last.

Thanks !!