A few more things that I have found, this is not going to be another rant since I can't sleep and figured that I could do something other than stare at the ceiling for hours...
Pre-Ordering Treasure Tracker in the UK will gain you a Toad Key chain:
Kind of courius that they would use him to serve as the pre-order bonus if they are not only supposedly different characters, but also already have 2D Captain Toad art to choose from such as the life icons and this:
That would be like advertising a Luigi's Mansion game with Mario plastered on everything.
3D World uses Toad's icon for the Captain, with the small addition of a headlamp:
Mario,Luigi,Peach and Blue Toad use their icons from other games as well.
Last but not least we have what's probably the most interesting thing of the bunch, the german Eshop description for Treasure Tracker:
Basically just a standart description of the game: the characters can't jump, puzzles, over 70 levels blablabla, what's more interesting is the fact that it treats the Captain and Toad as the same individual, this may not sound like anything huge, combined with all of the other sources things are really starting to pile up now.
That's all I got for now, still tired...