I think that a very importan question here is; does Nintendo want to colaborate again with the same publishers of FP1? Because if the answer is no and Nintendo wants to work with other publishers so they can bring more diversity to FP2, that means that we will not get more Sega, Square-Enix, Microsoft or SNK characters (IPs like Yakuza, Halo, Nier, Tomb Raider, etc). A curious “exception” would be Sora from Kingdom Hearts because the rights of the IP belongs to Disney. Its possible that they want to work again with Capcom and/or Namco-Bandai that don’t have DLC fighters.
Moreover, if Nintendo wants to work with other publishers, it maybe opens the door to characters from companies like Koei-Tecmo, Arc System Works, Level-5. Marvelous, Nippon Ichi, Falcom or even western publishers like Activision-Blizzard, Warner Bros or Bethesda.