Well it's been a couple weeks. here's what I've changed thanks to the suggestions in this thread. thanks to all who helped and suggested things to do.
Went back to straight promix bx, no extra perlite, no extra nothing.
Switched nutes to Dynagro Foliar Pro and Protekt
pHing water to 8.0 to offset the acidity of promix. soil and water slurry reads 6.7 pH.
Been watering 1 pint per gallon for waterings, about every 2-3 days.
Happy to report that all plants have bounced back and are growing like they should... FINALLY. Also happy that I have 3/4 of my flower room lights back on since I have the plants to support it, working to get everything to 100% capacity right now.
Related or unrelated: I had a room mate live with me to help with the bills for the past 4 months. He had access to the grow rooms in the basement since rent included use of the laundry machines, my nutes were easily accessible to be tampered with. Not saying that my old room mate did anything but I find it odd that in the course of him living with me my plants were doing absolutely horribly no matter how many different soil/nutrient combinations I tried. As soon as he moved out and buying new nutes that were untampered, all the plants bounced back in about a week. hmmm.