as someone said only if Kurt came back to marvel and gets the nod by them then only we can get such confirmation and it isn't too difficult avoiding mention of DC as Kurt himself did a story in Trinity about krona and the egg where he was able to avoid all mention of marvel and it was a reality altering story so he could revisit the premise here but it seems silly that DC magicians and representatives of oder and chaos were unaware of this magic and yet a outsider was able to access it. The crossover had another wrinkle in that there is no speed forcwe in MU when it was stated in rebirth that it exists in all realities in all time so maybe the two universes should stay seperate as they were basically shown to be incompatible and destroying each other when forced together.