Geralt is in a difficult spot, to be honest. The Smash team and Sakurai are japanese, working with a big company like Microsoft is something, working with a way smaller polish company is another. Moreover, the licensing may be hard to get for The Witcher, since it's probably at least shared with the book author.
If what's deconfirmed is true, the only real runner-up is Sony, honestly. Be it Kratos, Nathan Drake or
hopefully Ratchet & Clank.
However, I could see two other possibilities:
- Vergeben deconfirmed Square Enix, not Disney. But since the start, he is considering Sora under Square Enix, despite being a Disney character. He's in a weird spot.
- Vergeben listed both Activision and Blizzard, despite Blizzard being under Activision. Maybe deconfirming some of these companies doesn't deconfirm their own sub-companies, like Mojang owned by Microsoft for example.
Edit: I completely forgot but there's another runner-up, in Tencent and Riot: League of Legends