The whole job of tie-ins is to tie in -- to supplement a series by telling additional stories that could have happened in its reality. If our goal were to tell stories in a differing reality, we'd be writing original fiction. Sometimes there are parts of the series reality that we aren't free to mention directly, but we still have to set our stories in the same reality. And that means we can't contradict those parts, just work around them and focus on the other parts instead.