kb420, until you get more experience you should not be giving out poor advice.

1. Cotyledons pretty much always look like that. There is no unusual leaf curl going on.

2. The problem with those seedlings is multiple plants in one pot plus no tenough light, which is why one needs to be held up with a chopstick... at transplant, they can be buried right up to the cotyledons and will grow roots from that part of the stem so it's going to be okay.

3. You are lucky there's no browning yet but lay off the nutes to keep it that way.

4. Actual temps you need are a) not dependent on light cycle and b) lower than kb420 stated; temperatures at approximately 72-76 degrees F with good fresh air flow are ideal.

So your job now is to give them good air flow, MUCH more light, and as soon as they are a little stronger, carefully repot them into seperate pots. And no ferts until you see that the leaves have at least 3-5 fingers each, and at that point, start with a 1/4 strength solution for the first couple feedings.