The clones being in their own corner makes sense insofar as they're only marginally different and Sakurai might want to treat them like "bonuses."
That still doesn't make any sense. Melee's clones were also "bonuses," but they were still attached to their respective series. Characters should be grouped by series, and they have been for the last three games. What separates a "pure clone" from a "somewhat unique clone" is a completely arbitrary distinction -- there just isn't any reason for Toon Link to hang around the Zelda characters while someone like Dr. Mario (who probably wouldn't use the F.L.U.D.D.) is randomly thrown in at the end. A character is a character.
Yoshi being in the Mario row might just be Sakurai acknowledging that while he has his own series, he's still a Mario universe character. He didn't get his own title card in the first trailer, either.
Yoshi wasn't in the first trailer, so obviously he wouldn't get his own title card.
Feels appropriate to have him after the Mario vets but before the Mario newcomers since he still appears in Mario games to this day.
I don't see how that's at all appropriate. In Smash Bros. he still represents his own series -- he has an egg icon, his own stage, his own All-Star battle, and his own set of trophies. He still appeared in Mario games during the development of SSB64, Melee, and Brawl, too, but he didn't disrupt the main series characters in those games.
I'm just saying, the rules governing these matters might not be as rigid as we once thought.
Rigidity isn't my issue -- it's that Sakurai and his wife have exercised incredible sensibility and aestheticism in every game they've ever worked on, but this select screen throws all of those values out the window. It's ugly, disorderly, and nonsensical. It's set up exactly like the countless dream rosters and bad hoaxes I've seen over the years.
There's also the issue of the guest characters appearing in the order of Pac-Man/Mega Man/Sonic but the stages appearing as Mega Man/Pac-Man/Sonic. There's just a lot of all-around sloppiness.