So I'm thinking we have probably 5 characters left. 2 echoes, whom are 3rd party, and 3 Uniques, one of which is 3rd party.
-Ken
-Incineroar
-Shadow
-Skull Kid
-Geno
Reasons why:
-Ken: Likely leaked via a significant photo. Also Vergeben, whom at this point probably is right.
-Incineroar: Vergeben
-Shadow/Skull Kid: I treat them similar to Isabelle at the moment. Before I had all 3 as possibilities simply because they were replaced by another AT of the same game/franchise. Isabelle herself now helps supports this. Not because of chairs, popularity, or Loz18. I sincerely think Skull Kid is as much in the game as Isabelle due to the Moon, and similarly Shadow due to Knuckles. And before anyone mentions Isaac, Isaac was not replaced in Smash 4, he was just removed entirely. While I do think Isaac has a chance, it may be DLC to promote a future Golden Sun game (due to significant retrademarking)
-Geno: Vergeben's SE Rep. I don't think its Sora simply due to the fact that KH3 is not out yet, and if Sora were included, he'd likely be in his KH3 appearance and use a similar moveset to that version, so likely DLC (also its Sora you release him as DLC lol). I also don't think its Dragon Quest simply because while immensely popular and beloved (and I love it too), Dragon Quest does not bring anything new to the table via a Sword wielding protagonist, imo. Its very possible it could be Chrono, as he'd be the Toriyama design I could see being picked, additionally due to his unique flavor of moves and lore that could give him a decent moveset. However, I do think its Geno is coming this time. Many picked characters so far (K. Rool, Inkling, Isabelle, Chrom, etc) have had Mii Costumes in the past. Geno is by far the most significant one they made. He also is personally requested by Sakurai.
So I personally think next week may simply be just Incineroar due to the events revolving around him in Japan next week, leaving Ken, Shadow, Skull Kid and Geno as final picks for the last direct, ending at 71 characters until DLC is in order. It also goes along with Sakurai's comments, the rate will have slowed entirely if Incineroar is the only one next, however, revealing 4 final characters in the last direct seems decent enough to happen. Anyway I'm sure I'm off somewhere, but each of these characters have significant plausibility to being in this game.