Hi xgrendel, welcome!
Anabelle's leaf looks like it's been a little bit chewed on (slugs or grasshoppers, hard to tell). Some areas have already scabbed over with white, but that particular brown area has become infected.
Do you have a new, single-edged razor blade? If not, a sharp knife will do once dipped in bleach and allowed to dry.
Cut completely around the affected area--not into the middle of it--and remove the fungus. The leaf will be scarred, but that's okay. New leaves will eventually grow and you don't want this to spread. Dip a Q-tip into some rubbing alcohol or Listerine and swab the cut area entirely. If you have access to a fungicide like Capstan powder, apply that liberally to the cut, if not, no problem: the alcohol will more than likely do the trick and the cut will scab over in white.
The black stuff you're noticing on the leaf edges is mold: not harmful, but indicative of a touch too much humidity. Your rock / humidity tray is all you need for your growing conditions: no need to mist the plant at all. Just water every 4 days or so with a 1/4 to 1/3 strength fertilizer solution, and Anabelle will do great.
OrchidTracy here has had experience revitalizing Phals; she might have something to add...
In any case, thanks for offering to answer questions and, glad you're here!