Most recent article was very interesting. And I assume you've been over it a fair bit here
https://sourcegaming.info/2018/08/2...smash-direct-sakurais-famitsu-column-vol-561/
The two most interesting things are
1. Being very exact with stage count again, I'm convinced that this is the final count
2. Ballot absolutely having an impact.
To me, this screams Bandana Dee is getting in, while Isaac probably isn't due to stages (imo, wouldn't mind being wrong, don't hurt me)
As for Skull Kid, I think he'll be a "We get a lot of demand for a new Zelda character, and he's the most popular one" sort of deal, not necessarily the ballot. But maybe he did do well in the ballot? He refers to both Dark Samus and Chrom as popular picks despite both being deconfirmed in Smash 4.