I'm happy to report that there are already signs of reinvigorated growth. The areas on the first trues that were still green have swollen to twice the area they were last night, and the second set of trues have grown much bigger.
BTW: @Mad Hamish. Thank you for begin conscious of overwatering. That's what I thought my problem was initially. They're in 3 gallon grow bags so that I won't have to transplant, so it took a far amount of water to even see RO. Most of the H2O2 water was poured near the plants, and the nute water around the perimeter to allow the previously nute-less coir to absorb some instead of flooding the current, young root zone with nutes.
Thank you all so much for your insight and suggestions!