Let's check all the versions:
-The Legend of Zelda: too short for a ported version or a remix (in a similar way to Castle Theme from Super Mario Bros.)
-A Link to the Past: there is the "Hidden Mountain & Forest" remix
-Four Swords: it may be an option. Hope Nintendo still remembers that game
-Four Swords Adventures: itself a arrangement from ALttP
-Twilight Princess: as a ported version, it may be too much "tribal" for Smash. It has to be more melodical (I expect I made it clear. If not, I apologize for my expression). In case of being included, it may be remixed
-A Link Between Worlds: also an arrangement from ALttP, but we also have the Lorule Theme, which itself is an arrangement from ALttP, so maybe they may do it again
-Hyrule Warriors: probably not, as it is a spin-off not recognised in Smash Bros. Also, the style of music doesn't fit with the style of the rest of tracks of the saga.
-Breath of the Wild: as TJ-Works told before, it's too ambiental for Smash Bros. (And it is an arrangement from the 1986 version in the original The Legend of Zelda).
These are my thoughts about it. I bet for the Four Swords and the ALBW versions to appear.