Seedlings look fine, 3rd might be show minor heat stess. Your big plant look minor nute burn and possible pest problem
Just a lil bit man I see more bug bites then I do nute OD but no biggie but the lil guys look just a tiny bit more after ur flush/ reg watering cut back on the fert like less then 1/4 strength then work ur way up its like smoking bro u can smoke or eat more but it's real hard to unsmoke or uneat weed u already did right ? Best of luck