Sora had a pretty big backing during the ballot. I remember most of, if not the entire Kingdom Hearts community rallying behind Sora. Even the major Kingdom Hearts youtubers got in on it and were tweeting about voting Sora in the ballot a bunch. I'd say Sora had a larger presence than other third parties,
especially among casual fans that don't frequent sites like Smashboards or participate in fan polls like the many conducting during the Ballot. I'd also say he had great popularity in Japan, where Kingdom Hearts is
very popular. Even now posts about Sora in Smash Bros. get thousands of upvotes on reddit, and that's one community. HMK asked a Disney executive about Sora getting in Smash Bros. and said that it's something that the fans want
to his face. That was a couple of months ago. More recently, Sora made a Top 5 list of characters
expected to be in Smash Bros. by a major Japanese publication.
If you take a look at the logistical side, it goes like this.
Sakurai: "Hey Normura can I add Sora into Smash Ultimate?"
Normura: "Yeah bro. Sounds cool."
*Normura goes to Disney*
Normura: "Hey so I talked to Sakurai about adding Sora into Smash Ultimate and gave him the okay. Ball's in your court now. Bye."
*Disney starts sweating pennies*
Disney: "Hey so we're going to watch over you to make sure that Sora is faithful to the source material. That okay?"
Sakurai: "Yeah that's cool."
*Sakurai works on Sora, is mostly true to source material except for some minor areas where Disney pitches in*
Sakurai: "Cool we're done. Time to reveal him and go break the internet again."
Disney: "Cool. Nice
making money doing business with you."
*Sakurai makes finger guns at Disney, to which Disney awkwardly reciprocates*
There's a reason that I believe Sora is going to be one of, if not
the first DLC character for this game. He's too big not to be.