Well here is some exciting news. As noted previously, the twitter account for the Mana series posted a video of Seiken Densetsu 3 being played on Switcj, and now we know why.
Square Enixhas announced the Seiken Densetsu Collection for Switch. This will collect Seiken Densetsu: Final Fantasy Gaiden (Final Fantasy Adventure / Mystic Quest),Seiken Densetsu 2 (Secret of Mana) and Seiken Densetsu 3. It will be released physically and digitally on June 1st for 4,800 yen.
In addition to the base games, there are a number of additions Seiken Densetsu 2 and Seiken Densetsu 3 will support multiplayer with up to three players like in the original games, something that was not done not with any re-releases since. The games will also now include quick-save, which will allow you to save anywhere during gameplay.
There is also a Music Mode, which will let you listen to the music of each game from the home screen. Secret of Mana had a legendary soundtrack, so thi is welcome.. As well, there is a Screen Change Mode, which is a mode exclusive to Seiken Densetsu 1 that lets you choose from several screen sizes.
You can see a trailer for the collection here