Hisashi Nogami, is the only member of the Animal Crossing team on Splatoon. Nogami manages the Animal Crossing team and the Splatoon team. Produces both franchises. But they are separate teams, you can compare the credits. Besides, again the large production staffs are shared among Nintendo teams. It's only the core teams that are exclusive to each project group.
Soo imagine the main Nintendo internal dev teams
- The Mario Kart team
- The Pikmin team
- The Zelda 3D team
- The Zelda 2D team
- The Splatoon team
- The Rhythm Tengoku team
- The Tomodachi team
- The 2D Mario team
- The 3D Mario team
- The Sports/Play/Land team
- The WarioWare team (lol one guy)
They are all small core 3-5 man teams that develop the prototype, main mechanics, DLC elements. Then there is a larger production staff that shifts between them during heavy production periods usually 1-2 years before a commercial release. Well there are only soo many games that can be in the production phase at a time, even though all the small core teams exist.
We've seen Nintendo farm out the large production cycle sometimes (Platinum for Star Fox, Namco-Bandai for Wii Sports). More often than not though, those titles don't feel as good though.