Honestly, there are problems on all of them. Square Enix is a nightmare to get licenses from, so I don't think Nintendo will bother too much to get another FF or a DQ rep. Capcom could get Phoenix Wright and mayyyybe the MH rep, but they already have three reps there. Namco Bandai could easily get the Dark Souls rep, if only for the meme power (hell, it already has an amiibo). Nintendo could add whatever they want with their own characters.
I still want Octoling, please add octoling echo.