Phalaenopsis with leaf problems - sunburn or worse?

[Pulelehua]

I'm looking for help with a phalaenopsis that has tremendous sentimental value to my daughter-in-law. It was given as a gift 8-9 years ago to her grandmother who recently passed away. We call this orchid "the Queen" because she is quite large and produces an abundance of huge white flowers. She seemed to be flowering herself to death (9/16 - 2/17), branching from flower spikes with buds, prolonging any opportunity for re-pot.

I suspected she was in distress because she had not been re-potted in almost a decade. It was in a green plastic pot, so I could not see how the lower roots were doing, but the newer leaves are smaller than the others and there are also what I thought were sunburn spots on several leaves due to her being left outside for a month last summer. When her flowers eventually began to droop, my daughter-in-law brought her to me for help.

Using sterilized clippers, I decided to cut her remaining flower spikes to encourage root and leaf production instead of flowers and treated with cinnamon. After removing the green pot, I found mostly sphagnum, especially packed in the center. All lower roots were rotten so I removed them. There is a rather long base stem that was hard (not mushy). I felt I had traumatized this orchid enough in its already weakened state, so I decided to leave the stem for some support. I sprayed generously with hydrogen peroxide and allowed to dry completely before potting in only bark medium in a clear pot with side aeration holes. I watered initially and then weekly and placed in an east facing window with no direct sunlight. We are in a warm climate even in winter (60's and 70's at night / 70's and 80's during the day). At last check, we have 80% humidity.

I've noticed the 2nd leaf from the bottom (with what I thought were sunburns) is now turning yellow and is soft. I'm worried that I did something terribly wrong during re-pot or that the spotted leaves are a symptom of a larger problem.

Would someone please help me save this poor orchid?