Hi how ya doing ...... MrOldBoy here ..... Hope I can help ....
Question - what is the temperature at plant level - I ask because you mentioned something about lights and being able to stabilize temps hanging X inches from plants - also mentioned was lower end of temp range .......
Young plants like 80+ temps, I start mine at 85 degrees and they stay at that temp for a few days and then slowly down to around 78-82 degrees but only after the second set of true leaves due I lower much below 82 degrees .... Humidity I like to keep around 70% when young so until we know what the humidity is in the tent it’s probably best to keep the dome on and yes vent the dome .....
Plants should be able to grow to around 14 days minimum before needing any fertilizer- soil should have plenty already, in fact, your soil could be too hot for a start - you might wanna think about getting some organic starter soil such as Espoma Organic Starter Soil or Jiffy Organic Starter Soil and make a pocket / hole and fill with starter mix and let them grow into your Fox Farms .....
Good Luck!
Peace,
MOB