If so, the wetness on the leaves acted as a magnifying glass and burnt them. Not much you can do about it now, keep doing the normal routine and hope for the best.
Her plant is showing no signs of light stress at her current distance. Personally I would leave it there and ad the previous lights she was using as side lighting.
12" should be fine if it's one plant.
You transplanted a little early so it may have slowed down growth, otherwise she looks healthy so just give it time.