This weekend I attended Planet Comicon in Kansas City, MO.
MIng-Na Wen was a guest at a Q&A session I attended. For those that don't know, she is currently Agent Melinda May on Marvel's Agents of SHIELD, and is also the voice of Mulan.
I don't recall what someone asked her, I think it was a child that brought up her love for Mulan, but Mina-Na hesitated a bit not sure if she was allowed to tell us something, but then she went ahead and stated that Mulan is slated for Disney Infinity 3.0.
I hope she doesn't get into trouble for letting it slip, I'm not sure how tightly Disney would keep something like this a secret. I recorded her session, and the audio is available on my podcast, but I don't think I'm permitted to link it to this topic. I have video of it as well, and I plan to put it on my YouTube channel.
I mention the audio and video mainly just so you know I'm not just starting a rumor, but confirming that Ming-Na Wen has said that she has voiced Mulan for DI 3.0
Whether she will be a toy box exclusive or if maybe we get a play set, I don't know, but I would guess she'll be a toy box exclusive.