Four Swords and Four Swords Adventures are canon entries in the main Zelda series, so technically on the same footing as a Majora's Mask or A Link Between Worlds, as much as it pains me to say and wish they weren't. They were a small effort sure, but they're still one of the 'Legends'. Doesn't matter, but I thought I'd just mention that .
Anyway, I think Hyrule Warriors will outsell it. The publisher and dev are hoping for a million and it's halfway there. It is over halfway to Four Swords Adventures already. With the holidays still coming I think it should be able to.