Mario Maker is probably the biggest thing not yet announced for the Switch that would make a lot of people happy and also be online, so it could fit either game description. Pikmin has been confirmed to exist but not formally announced yet much longed for by fans, so it could be that, niche or not, since the quote just says "fans will be delighted to know" meaning it could just be "fans of that franchise", suggesting it's something with a lot of fans actively clamoring for it. From that perspective, it could also be F-Zero, though that feels more unlikely since they've multiple times expressed that they've no idea what to do with the series (somehow, even though it should be obvious), or a return-to-form Paper Mario, which also seems unlikely as the Paper Mario developers seem to be way too stubbornly attached to their new philosophy to have learned their lesson from the past two entries yet. Mother 3 honestly seems more likely than either of those two, but still not as likely as Pikmin since, well, it's Mother 3, and Nintendo hates us, and we likely won't get an official translation until 2067.
The Star Fox racing thing, I honestly think is canceled due to Retro being moved full time to Metroid Prime 4. So I don't think that's the online thing. Kind of surprised anyone wants it. Every other time Nintendo has tried to make a Star Fox game that plays even slightly differently than 64, like Adventures or Command, fans hated it. Personally, I'd rather have F-Zero than Star Fox Grand Prix. Hell, I'd rather have Adventures 2 than Star Fox Grand Prix. It just sounds stupid to me.