1st Grow, Holy Grail Kush, DWC w/CO2

I had 3 days of germ counting the paper towel and rockwool sprouting. I'm calling this week seedling wk 1 for my own personal records. I'll record it as veg when rapid leaf and root growth begin. Seedling Day 1 8 of the seedlings are standing, and the others are beginning to emerge. I'm misting the cubes every 6 hours or so go keep them from drying out. One of the seedlings tore one of its own cotyledon off during emergence. I'm wondering if it was a planting error on my part. Day 2 The tallest seedlings are almost 2 inches, and almost all have emerged from their cubes. Some still have shell pieces clinging to or partially enclosing their cotyledon. I began working the PPFD up from 100 to 200 throughout the day. Still holding temps in the high 70s and humidity 90 to 95%. Day 3 Not much change, some seedlings are rising from the cube but are still stuck in their seed shells. I'm worried they're going to end up needing help. I went to 18 and 6 hr light schedule and started the first night cycle at midnight. Day 4 The temp dropped to 70 degrees during the night cycle. I will work on stabilizing that. I helped get a few easier to remove seed shells off of cotyledons. I've got a few that look like they're in a real bind though, I'm strongly debating trying to help but I'm concerned about hurting them. *update- after advice from @hashy I misted them a couple times throughout the day and then undertook the rescue of the three trapped in shells. It was difficult trying to gently handle the seedlings while getting the firmly stuck shells off, and I'm surprised I didn't do more damage. I don't belive the third one in the pics will survive, I think its cotyledon might have melted/rotted in the shell. Day 5 I filled in the loose holes around the stems with slivers of rockwool. Next time I'll plant the seeds sooner instead of opening the home up to accommodate the longer roots. I mixed up 1/4 strength nutrient solution and gave 1 liter to the bottom of the germ tray. I also raised the PPFD to 300 about 4 hours before lights out. Day 6 I'm attempting to maintain temps from 78 to 82 degrees and bring the R/H down to 80-85%. One of the rescued seedlings appears to have died. Slight growth visible from the healthy seedlings. Almost all "true leaves" are bigger than their cotyledon now. Plants are 1" to 3" tall. Day 7 I removed the dead seedling from the germ tray. I checked 4 of the cubes, all had varying amounts of root growth showing. The 4 seedlings on one end of the tray have clearly purple stalks as opposed to the light green the rest of them display. I'm rotating the germ tray to see if maybe its a difference in lighting or nutrient solution pooling in the bottom of the tray. The one I checked with a purple stem had better root development than any others.