Looking good!
I have a tray of seeds that did not sprout either. The only thing that came up was marigolds, probably because they are so sturdy, but nothing else. :/
It was my own fault though. I watered them in with water from steaming veggies, which apparently is very prone to molding!! The mold came on fast and killed off my marigold sprouts.
Lesson learned. Only water them in with plain water!!