Poor Toad :C
But well, here is my opinion.
Toad and Bandana Dee are in very different situations.
First, Toad was showed in a picture with the other characters of Mario 3D World, is like: Here are the heroes of the Mushroom Kingdom, but one is just an attack.
Then, this picture was posted before Rosalina's reveal.
Is like: Nope, Toad is not playable.
And obviously, then we have Rosalina's reveal.
I know a Blue Toad is not technically deconfirmed, but another Mario character is not likely, he has a lot of competition and is exactly the same as the other Toads (Red, Yellow, etc), Blue Toad isn't even "The Toad", there is a lot of Blue Toads, so, imo, if Sakurai "deconfirms" one Toad, he "deconfirms" all the Toads.
Maybe Captain Toad or Toadsworth have "a chance" because they are important members of their species, and obviously they are more than just a Toad with another colour, they have an important role, they are unique, and they look different.
Too bad they have a lot of competition, their series probably won't have another newcomer and they are not popular.
But Bandana Dee is different, a normal Waddle Dee is just a normal enemy, not an important character, Bandana Dee has an important role, he has moveset potential and is an expert with the spear, a warrior.
A normal Waddle Dee can't do what Bandana Dee can do (Normal Spear Waddle Dees are just novices.)
If Dedede is in a pic throwing a Waddle Dee, what would happen? Bandana Dee looks pretty different, he is reddish, has a bandana and a spear, he can even kill other Waddle Dees in the Wii game, so I think that would not affect his chances.
You can't compare a normal enemy to an important character, That's one of Toad's problems, all of them are the same, all of them has the same personality, can do the same and the only difference between them is just a colour change.
BUT, if Sakurai posts a pic of Kirby, Meta Knight , Dedede and a normal Waddle Dee, like in the pic with Toad, I think Bandana Dee would probably be deconfirmed, but I doubt that will happen.