Got the humidity issue taken care of, fixed the temperatures, and moved the main bulb in the tent from MH to HPS. In doing so, I added around 450w of LED light to the tent to compensate, and turned the main light down to 75% (of, 600, so in theory, I'm running 900 in the tent right now).
Also ended up using an additive 'Real Growers Recharge'. They looked good before, so no word on if they helped, and the heat/humidity/etc stress probably didn't help, which started around the time I added that additive.