Well, we somehow managed to survive the slaughter of characters that was the Smash Bros. Nintendo direct, which also took away another competitor of ours, Midna, who was a large competitor back in Brawl. Seems like Vaati's the only one left that was huge in Brawl's time that's not in the game in some way. (The huge guys were Midna and Toon Link btw) and each Zelda newcomer seemed to get hit with some blow, with Tetra it was the Bombchu, which many predicted would be one of Tetra's moves.
With Midna and Skull Kid, we already know what happened to them
Tingle, while it seems that he was safe, I believe will be appearing on Termina Bay. As for why I think Termina Bay will be brought back, Skull Kid for some odd reason doesn't have anything to do with the moon falling, which happens on Termina Bay, which if confirmed, would largely hurt or even deconfirm Tingle.
It seems as though Ghirahim and Vaati were the only ones who weren't hurt due to the direct. Hopefully this will help point Vaati into the playable direction.
I'm glad I'm not the only one with that same theory on Tingle.
It's especially viable because also:
1. Melee stages confirmed to return (Jungle Japes)
2. Majora's Mask references and possible remake could lead to a stage being almost necessary
And you already mentioned how Skull Kid doesn't have the moon.
I think Toon Zelda and Tetra were also hurt because:
1. They are now in competition with each other due to transformations deconfirmed
2. We already have a 2nd Zelda playable with her own slot in the form of Sheik
And less significantly, Toon Zelda was hurt by:
1. Greninja being very unique like the rest of the newcomers
2. Wii Fit Trainer finally showing that she has been unique the whole time, with her own gimmick.
Not looking so good for a Zelda clone at this point, you didn't mention...
Impa was hurt by:
1. Sheik confirmed, 95% of her fans wanted her to replace Sheik
2. Less significantly, Greninja was confirmed. There are 2 ninjas now. She's just not happening.
Classic Ganon was hurt by:
1. Transformations deconfirmed
A good amount of his supporters, including me, just wanted Dorf to transform into him. Not him as his own slot.
Ghirahim was possibly helped because of the Fi trophy, and all of the SS references with 2 more TP characters confirmed. We don't have SS characters.
Vaati was helped by the lowered chances of every other toon character.
Both were helped by less competition, both also both were significantly helped by Midna as an Assist Trophy
For a popular character only in one game but prominent in that game... we had Ghirahim vs Midna
For a character Sakurai had seen the large fanbase of pre-Brawl that he'd have in the back of his head till the new game situation... we had Vaati vs Midna
Ghirahim and Vaati are lookin' pretty alright right now.