Based on names used by Britain's royal family in the past, some experts believe that contenders might include Arthur, Albert, Philip or James.
Authorities have charged Alan McGinnis of Pemberton, New Jersey in the stabbing death of Cody MacPherson, 20, missing since September.
LGBTQ advocates say the change is "a step in the right direction."
Police said Monday afternoon's van attack in downtown Toronto "definitely looked deliberate," but downplayed any potential connection to terrorism.
"We were confident that Madonna had no claim whatsoever, and the judge clearly agreed with us."