George Foreman told people in Pittsburgh this week that he wasn’t going because he didn’t want to be a distraction. He’d pay his respects privately. That takes a lot of class as I understand him and Ali were close friends.
Donald Trump wanted to go, but I don’t think he did, or we would have heard about it by now. Trump knew Ali quite well.
He can always raise the topic later, after all the pageantry and ceremony of Ali’s funeral.