Recently repotted mini-phal from sphag to bark mix: roots shrivelled/rotting

[Bahar]

Ten days ago, I repotted a mini-phal from 2 in pot in sphag to a 3 in pot in medium orchiata mix with charcoal, perlite and a bit of sphag (Ray's Better Off Moist). Within 24 hours, i noticed a couple of the once healthy roots shrivelling up, and now all of the roots have done the same. The only part of the roots that are still firm are the portion of the roots near the base that were/are not in the medium. I've read that some phals don't tolerate going from moss to bark. since I potted this one the same way I repot all others (using physan, wearing gloves, sterilizing tools, cutting off dead roots, etc) and it's the only one having a problem, I think it's the moss to bark transition.

I ordered KLN yesterday and expect delivery by tomorrow. Should I take it out of the medium immediately? If so, what then? I was thinking about cutting off dead roots, soaking in physan and then putting it in a vase or bowl with water in the bottom (keeping what few roots are left above the water. Should I do this?

What should I do once I get the KLN?

Before repotting, this plant had an abundance of thick, healthy green roots with green tips. It has 5 leaves, but a bottom one is yellowing, and the one above it is starting to wrinkle. It still has the old flower spikes (they haven't dried out and i normally don't cut them off unless they do). Should I cut them both off so the plant can use its energy on growing roots?

Also, I noticed white mold on dead roots 3 days after repotting. I doused it in listerine, and the mold appears to be gone.

I have the plant in a shaded area near SE window. The temp is 69-73 degrees. Humidity right now is 75%. Have a ceiling fan running constantly.

I would appreciate any advice as to what to do once I unpot and trim dead roots!!