If one of the guys in BFS wanted to wrestle and name himself Alexa Bliss, it would be a problem. But using a trademark in a song in a non-damaging way needs no clearance at all. Way back when "Barbie Girl" was a hit, Mattel sued the band and even went to the Supreme Court, no chance, case dismissed. Her appearance of course needed to greenlighted. She can't perform anywhere as Alexa Bliss without permission.I'm not really sure how that works. If BFS just wanted to write a song about her and release it I don't see how Vince could stop that, but I guess with Alexa being actively involved in the video they probably had to give their permission.