My speculation for the five DLC newcomers is still this:
1. Square-Enix newcomer: This slot has been leaked by Vergeben, but the identity has not. Geno, Sora, and a Dragon Quest character all have strong points each in their favor. Geno is personally favored by Sakurai. Sora is the protagonist of one of the biggest franchises not yet repped in Smash Bros. Dragon Quest is the last big Japanese gaming franchise dating back to the 1980's without any sort of content in Smash Bros.
2. Namco-Bandai newcomer: With Sega, Capcom, Konami, and soon Square-Enix (even if it ends up being Geno) all having two or three playable characters in Smash Bros., it seems very strange that the developer of Ultimate would not get a second slot too. The most likely characters for this are Heihachi (who is oddly missing as an Assist Trophy, when Akira from Virtua Fighter got promoted) or Lloyd Irving, the most popular and well known Tales character. It is also possible a character from Soul Calibur or Klonoa could be chosen.
3. Banjo-Kazooie. They were among the strongest ballot performers on the Western side of things. Microsoft has expressed interest too in seeing the character in Smash Bros., and they even allowed for Microsoft owned characters (from Banjo-Kazooie and Halo) to appear in the Nintendo console ports to Minecraft. Cross-play between the Switch and Xbox ports of Minecraft was also promoted at E3. I think Vergeben's Minecraft content is probably a stand alone stage and some music, and Banjo-Kazooie will also come in as a newcomer with their own stage.
4. Bandanna Dee. He had a bunch of critical roles in the interim between Smash 4 and Ultimate. He was Kirby's sole side kick in Rainbow Curse and Battle Royale. At this point he could very well be the most wanted newcomer on the Japanese side of things. Moreover, he is among the few major Nintendo characters who does not have any sort of notable NPC role in Ultimate, not even as a spirit.
5. Elma. The near complete absence of Xenoblade X content in Ultimate is extremely suspicious. Even Metroid Prime 3, which was released only a few months after Brawl in Japan, received notable content in Smash 4 in the form of Assist Trophy Dark Samus (while the rest of Metroid's new content was stuff pulled from Other M). Xenoblade X having less content than Xenoblade 2 is extremely odd. I would not be surprised if Elma's release is being timed with the announcement of an X port or sequel to the Switch.