Nice post and great info. I'll see if I can help (along w/that of others ...)
First, the Humidex system may be contributing to your problem. In order to REMOVE the air from under the floor, it has to be replaced with air from some place else. (Air Out = Air In) In short, I'd turn that system off for now.
Secondly, I'd open those vents in the crawlspace (to the OUTSIDE of the house.) Let Mother Nature do her job. Now that you have the 6 mil plastic down and the French Drain system in place, you should have dramatically reduced/elimated your moisture problem. Don't worry about the nail holes in the felt. If some moisture wants to come up through the floor, let it. The holes aren't that big and there aren't a 1000 of them. Oh, make sure you have something weighing down the edges of your plastic. Use gravel or bricks or PT lumber or something that won't rot. The installation of the Humidistat will be kinda a novelty unless it's hooked to something to remove the moisture. For now, I'd hold off on the dehumidifier too.
Don't add any heat under there. Warm air holds more moisture. Again, let Mother Nature do her work. Hold off on any cross-cutting of the boards. Forget the ECS w/the HVAC system. Forget about concreting your crawlspace floor too.
Soooo, you're left with opening the vents, leaving the floor covered w/plastic, and basically, doing nothing else. NOW that that's all taken care of, what about those cupped boards? I'm hoping that with all you've done, that over time, the humidity will drop and the boards will 'shrink'. OK is known to get 'dry' so I'd let that happen. Worst case come to worst, you can relay the floor. Again, wait for others to reply.