I would take all the sphagnum off. I can't tell from the pictures about the roots. Do they look firm and alive or limp and dead? Trim off any dead roots. I would keep the roots just on the medium and mist once to twice daily. Don't cover them up. Orchid roots often like air and light.
I have planted the orchid in moist sphagnum with a humidity bag on top. I am hoping a new growth will activate and it will start to grow roots. (it is rootless). I have provided a more airy mix, any further steps that I can take to help my orchid? species is chirrhopetalum mastersianum. I hope he pulls through. any help would be very appreciated.