You know, I really feel bad for Sakurai right now. Regardless whether the leak is real or fake, he's kind of ****ed one way or another as this roster is literally ideal. If real, amazing, but the whole roster save for the next reveal would be completely unsurprising (the next reveal would be okay because even if it's any of the leaked characters, we won't know for sure if it's real until we see the banner). If it's fake, then a lot of people are going to be disappointed even though this game has so much work and passion poured into it. This roster would blow everyone's predictions out of the water in the best way possible, and especially given the circumstances it'll be really tough to top a roster like this if the leak is fake.
They have to be looking at this one way or another as it is getting MASSIVE attention and coverage. If it is in fact fake, I think their best course of action would be to put up a reveal ASAP, just to rip the proverbial Band-Aid off and give people time to adjust. Because the thing is, no matter how great the roster we got so far is, people will be disappointed if it's anything less, which is a shame given how amazing the content so far has been.