Coming along great, looks like an early sign of some sort of deficiency, possibly magnesium or a calcium but really hard to tell. The petioles look purple which can be a sign of mag or phosphorus deficiency. What is the Ph of your feedings? Without going through the 11 pages, what are you feeding the girls?
Seedlings look overwatered. I’d allow them to dry back before next watering. And you mentioned having someone mist them daily, I would avoid watering daily especially seedlings, that’s how they get overwatered even if it’s only an oz of water every day.