Mario 3D All-Stars also had references to Pikmin back in 2020, however I don't think it was related at all, due to how it used prefix and Pikmin 4 was in development at that time either way.
Star Fox to me makes a bigger sense as a middle to end life release on a console. It was refferenced in Switch Sports, yes but it does not mean it will be made at EPD4, I actually think it's impossible given what stuff they are producing. It does not line up very well with what they are doing.
Emily said that in December 2019, and I quote:
Yugo Hayashi was Star Fox Zero Director, he then moved to work on Super Mario Run, ARMS and latest on Mario Kart Tour. He was also part of the "Star Fox Team" in Star Link credits. So is EPD9 the most likely group to take over Star Fox? But I assume he was credited in Star Link just because of his ties to Star Fox as EPD9 is working on new Mario Kart either way. If DK can be back internally at EPD why can't Star Fox be too? There were these ideas that Ubisoft should make a Star Fox game and if that happens some day, then Nintendo is in deep trouble.
I don't think future for Star Fox looks to bright now however, Imamura already retired, Miyamoto is (was) busy with other stuff like theme parks, movie and Pikmin (yes, he is not that much involved in development anymore but he is the one who will be pushing for this project more). Not to mention that Tadashi Sugiyama (Star Fox Zero producer) was not credited on anything since Tank Troopers in 2016 so is likely that he left the company.
But probably in like 2025-6 we could see something, and hey there is always Star Fox Grand Prix.