It's not confirmed, just one of the more popular rumors. Beauty and the Beast, Mulan, and Tron are the other leading rumors.
Mulan is out, JV confirmed recently the last 2 are from the same franchise. Mulan doesn't really have a secondary popular enough to get in.
Mushu - very low rate, not happening
Shang - to similar to Mulan nothing unique if Mulan is in
Shan Yu - not a very unique villain
So that combined with
1. One is a female
2. That female is possibly a princess
3. The absolute secrecy about them going so far as to completely remove and hide all evidence of them.
4. They will not confirm that there is no Disney playset, despite there being only 2 characters left that aren't confirmed ToyBox only.
There is only 3 things that warrant the hype and saving the reveal.
1.
Beauty and the Beast Playset = not likely worth the trouble of removing/hiding data instead of just a big trailer.
2.
Little Mermaid Playset = can't happen yet, no water in infinity and no swimming and such animations
3.
Live Action Cinderella Playset = releasing in March, only one pic has been released so far.
I think they will reveal Cinderella, Charming(Robb Stark from GoT) and Playset within days of the full trailer.
Damn it, Cinderella is one of my favorite Disney films and I don't shitty designs based off the movie like the maleficient figure.
I know classic Maleficent is such an iconic villain and we get a dull generic one.
Come on now.
Funny though I would take Once Upon a Time versions of Snow White and Charming though.