That other character is from Subcon in Super Mario Bros. 2 in USA or Super Mario Bros. USA in Japan you save those characters in that game. In this one however I have no clue who the boss is maybe Wart since peach is playable again since the last time you played as her you were facing wart in SMB2 or SMBUSA in Japan.
Here is my to get list for 2013 since I have Luigi's Mansion Dark Moon and am about finished with it:
Sonic Lost World Wii U version
Mario Kart 8
Some of these I might have to hold off on for a bit until I have more funds too.