As others have pointed out, this leak is so fanservice-y, that too from a Western perspective, I find it hard to believe it. Sure, I'd love to see it being true though.
It has some plausible things, but I find other things hard to believe and they didn't mention other key things.
-Takamaru is not mentioned even once, and he is considered the most likely retro rep.
-Shulk is also not mentioned once, despite being one of Japan's most wanted characters and Sakurai posting a pic of Shulk's sword, the Monado, on his Twitter.
-Doubt Waluigi was considered.
-Doubt that we are going to get Ridley and Palutena. K. Rool is still possible to me.
-I think Wario's default outfit will be his WarioWare one as the concept shows him wearing it. His overalls will definitely return, however.
-Making Ganondorf's down special his sword seems odd.
-He mentions that Mewtwo and Lucario have different movesets when they had different movesets to begin with.
-Sorry Tingle fans, but he doesn't seem like a likely newcomer to me.
-Isn't it odd that one of the WFT's attacks are different from the two genders?
-It doesn't mention other things that people want, like Mario getting a Dr. Mario alt. or Luigi using his Poltergust.
-No mention of Miis.
-There should have been at least one mention of Roy…
-The leaker is confused about the tripping aspect.
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No cuts happen. This is the fishiest one to me. Sakurai even apologized prior to the people who liked certain characters, meaning that he can't bring every single one back. Cuts are going to happen.