Another possibility: Doug's chaos field had a, ... unique, ... interaction with a Potter-verse spell and linked to another reality.
I can't see Yang being a simulcrum, as Doug's simulcrums are aware that they are not the real people.
___________________________
"I've always wanted to be somebody, but I should have been more specific." - George Carlin
I can't see Yang being a simulcrum, as Doug's simulcrums are aware that they are not the real people.
___________________________
"I've always wanted to be somebody, but I should have been more specific." - George Carlin