Fungus one week after repotting, why?

[LisaK]

I repotted my two mini orchid plants. I sterilized everything in bleach first. Then I removed the old medium, sphagnum moss that it came in and I washed them by hand. I even soaked them in tepid water and they seemed to love it. I cut off any brown dead spots, not many. I sprayed them with a neem oil spray. I bought sphagnum moss from amazon that was highly rated by many people. It looked great. I dampened it with bottled water and sprayed it with a cinnamon soap solution. I also sprinkled cinnamon on the roots and I fear I used too much. I watched an external root that I accidentally broke while repotting dry up alongside a perfectly healthy one that got cinnamon on it. It was then I learned cinnamon was very drying!! It killed a good root.
For a week I put them in the center of the kitchen because I read that it is best to keep them out of their normal amount of sun while they are recovering from being repotted. I think it was a mistake. A week after repotting the medium was almost dry and that is when I read about how drying cinnamon is. So I watered them with bottled water to rinse out the powder and sprayed them with the neem oil spray again. Within two days the roots became black in some spots with a blackish greenish whitish fur, which online is said to be fungus. (didn't take a photo)
Could fungus have grown in one week after repotting? Is it the new moss, it is perfectly dry out of the bag? The pot is only a half inch larger than the old one, as the roots were coming out of the pot and getting tight. Could it be the neem oil? It was the first time I used it on them in the 6 months I've had them.
My guess is that it was the fact they were on the kitchen table 10 feet from the window instead of on the north window sill where they were pretty happy.
Do I have to repot even though I just did it a week ago since the fungus grew on it. I sprayed it this morning with 1/3 hydrogen peroxide mixed with 2/3 water and flushed out the medium with it. No sign of the fungus except some parts of the roots are grayish black now.
I think I need to clarify why I used neem oil spray and the cinnamon spray. I have attached pictures (first pic 1.1) shows these round spots that appeared out of no where several weeks ago. I sent many emails out for help and had many different guesses on what it was, scale, mites, bacteria? But the common thread was the cinnamon spray and neem oil. So I tried both to cover my bases. Since then I have seen some sunken in spots on the tops of the leaves. And it looks like the leaf is dying on one right under my new baby flower spike!
I would love to know anyone's expert opinion!