The 3DS and Wii U versions of Smash might have the same roster, but for whatever reason, the order in which you unlock the characters different. And if you're curious as to how to go about unlocking these characters, you've come to the right place.
GameXplain has this informational video which breaks down the character requirements. Basically, you need to complete a certain amount of matches for each character (or you can try some alternate methods, described here by TAY). If you'd like the easiest method in text form, here you go:
Falco: 10 matches
Wario: 20 matches
Lucina: 30 Matches
Dark Pit: 40 Matches
Dr Mario: 50 Matches
ROB: 60 Matches
Mr. Game & Watch: 80 matches
Duck Hunt: 100 Matches
And like last time, you can speed this all up if you set up 1-stock matches and instantly suicide. Those matches will count for your total! You'll still have to beat the new challenger in order to unlock it, of course.
As for stages—since the 3DS and Wii U version have some differences in stages, the fact the unlock requirements are different makes sense, too. Here's what you need to do in order to unlock all the stages:
Kongo jungle 64: Clear the "The original Heavyweights" event
Duck Hunt: Get 1 or more KOs in a single Solo Cruel Smash
Pokemon Stadium 2: Clearn the "When Lightning Strikes" event
Smashville: Clear the "Playing Tricks" event
Flat Zone X: Play alone and as Mr. Game & Watch and destroy 100-blocks in a single game of Trophy Rush
Pac-Land: Play all the maps in Smash Tour
Super Smash Bros Wii U: Unlock All Secret Characters & Stages Guide [GameXplain]