1- Looks like bug damage, specifically thrips.
2- Same thing, the tacoing isn't anythign to be concerned with
3-Very slight tip scorch probably from the grow big. No serious problem.

Your seedlings look fine; take care of your bug problem asap. When the plants are healthy with 4 sets of adult leaves, you can bomb the room twice with pyrethrin spaced 3-5 days apart. Or get a pyrethrin spray fogger and use that several times. I always wait on the chemicals until the plants are old enough to be fed.