According to some, Amiibo Festival is a harmless "free" spin-off, while SFZero is AAA or an important project. Not the same.
Ok well, I don't think you can really fully say that till the game comes out and you can play it. we've seen a couple of videos and that's it.
Mario Tennis was less ambitious, and it's sales show. It may not be AAA series and you could argue its a spinoff but in the 2000's the two games comparitive sales have been close.
Starfox is what it is, never going to be a massive seller, but could still be a great game series (like Pikmin). The new one might be terrible, but like ive said I trust the two companies working on it.