Oh boy - lots to think about here...........
Actually, I can't be certain from the picture alone, but the first picture - on the right side of the base of the plant, above the root base appears like it is a FLOWER SPIKE. Of course 99% of the time when we see these we go, "WOO HOO!" In your case, if this is a flower spike we go, "BOO HOO" -
Sometimes in a last ditch effort to survive a plant will send up a flower spike that will have a few flowers on it - hoping to polinate and then make seed and carry on life in the next generation. With this effort often goes a percentage of the energy your plant needs to recover. Therefor, if I'm correct I would recommend snipping this off once this is confirmed. You want the energy of your plant to go into rebuilding roots at this juncture - others may think differently, but this is my two cents worth.
Mixing sphag and bark wouldn't necessarily be a bad idea in order to keep some moisture around those suffering roots, but a ball of sphag surrounded by bark wouldn't be something I would get too excited about. I guess it wouldn't hurt too much - it will probably dry out your sphag faster (?). I'd be inclined to stick with loosely packed sphag only (I would personally use coir mix because that is what I'm most comfortable with and have found works for me - but in theory the sphag should do the same) and then just check it every day to make certain it is slightly damp but not soaking wet. The warmer and more humid you can keep it the better - the cool temps you noted probably were a factor in the plant not drying out soon enough to start with. I wouldn't be at all surprised if you were to loose one or two of your leaves before the plant turns around - just because there is not currently enough root to support them - time will tell. Many of us on the forum use Superthrive as a root stimulant - you can find it at just about any garden center - places like Walmart, Fred Meyer, Lowes, etc. A small bottle lasts forever. No fertilizer for awhile. You can take a peek every few weeks and see if your roots are making any progress - won't hurt a thing. Keep us informed - these kinds of exercises are learning experiences for others when you share of what you did and include a pic or two. Good luck! mike