Sabi getting the cease and dsist wasn't because of some silly "leakbait" theory. It's because she had correctly leaked tons of correct info and she probably would have leaked the Direct. Her downfall was that she was getting too ballsy in announcing she would be leaking ****, and of course Nintendo was going to take action against that. This is nothing to do with characters being leakbait or not.
Plus, Shinobi still hasn't backpedled or clarified his original tease. If he had any doubts, I think he would have said something by now. He has like an 100% track record, including leaking Ultimate before it was announced. Why would be be suddenly wrong this time? I think the reason why he gets away with his leaks is because he's so cryptic.
I also think that Verge is extremely confident in his source, but he doesn't know which order Banjo and Erdrick will be revealed. That "1%" is hardly enough room for him to backpedel as if he's wrong, people will call him out on it. That 1% isn't going to save his ass.
Also, with the exception of Corrin, when has a character ever been used as shameless advertising? That's the only time I've seen that happen.
There's no reason to give up hope just yet.