I would say they are still too small to take their chances in the open garden, especially if you have slugs or snails. They could be gone in a night. If they have been under lights up until now did you harden them off before putting them outdoors? If not they will have been shocked by the sun and wind. I would pot them on, harden them off and and grow them on (in their pots) until they are a good deal larger before setting them out.

I just brought them out from under the lights. How should I harden them off?
Then put them in individual pots, and leave outside?

You can repot them either before or after they are hardened off. To harden them off you need to take them outside to a shady location for an hour or so. Then back in. Increase the time each day until they are out all day and all night.

They look rather wet since I can see green algae on the surface of the medium. You could ease off the water. But when you repot make sure they do have an initial good drink and drain.