This contains all of the characters revealed up until now as well as the following veterans:
-Wario
-Mr. Game and Watch
-Ganondorf
-R.O.B.
-Falco
-Ness
-Doctor Mario

As well as including newcomers such as:
-Bowser Jr. (In the Koopa Clown Car)
-Duck Hunt Dog
-Dark Pit
-Shulk

Of interest to note is that the following veterans that are missing from the above image and are theorized to have been cut are:
-Ice Climbers
-Lucas
-Ivysaur
-Squirtle
-Snake
-Wolf

It should also be noted that there was a DLC list floating around including Lucas, Snake and Wolf among others, but this is now believed to be likely faked by a copycat leaker.

In addition, a number of other photos were also included in the orignal 4chan post leaking the roster:




Along with the potentially leaked roster was the stage select screen. It shows previously revealed stages such as Golden Plains, Rainbow Road, and Tortimer Island but also reveals some never before seen stages such as a Yoshi stage, a F-Zero stage, Distant Planet, and a Xenoblade stage (which looks like Gaur Plains).


As well as more images:





An entire album's worth of leaked images here.


All-star Mode. Which is apparently locked as seen by the lock on the upper-left corner. (Suggesting that there are still some characters missing in that leaked roster image.)

And finally, several low quality videos have been posted on youtube showing off Shulk and Bowser Jr. They have since been taken down by Nintendo, thus confirming this leak to be real once and for all. Here's a list of some of the moves shown off by the characters:

Bowser Jr:
- Lick attack (f-tilt)
- Paint Brush (u-tilt)
- Cannon (either neutral or side special)
- Eject (Up- Special). Bowser Jr Leaves car, car explodes after a second
- Tosses Koopa mechs

Shulk
- Ability to change modes confirmed (Blue and red seen thus far)
- Whirling sword swing (d-smash)
- Marth-like recovery (up-special) (He yells out "Air Slash!" during this)

Here are some gifs from the Shulk video:





So that's it for the relevant info I could dig up. Thoughts? I'm personally super-hyped for Shulk. Duck Hunt seems like another one of Sakurai's crazy additions like R.O.B. and Wii Fit Trainer, interested to see how he plays. Kinda dissapointed that Dark Pit is most likely a clone, as Uprising's great variety of weapons could've made for a more original character, but I'll wait and see just how different is he from Pit himself. Doctor Mario is a strange choice for a Melee rep. Bowser Jr's gameplay mechanic of always being in the Koopa Kart looks interesting enough for me to check him out.

As for the cut veterans, while I don't care much for Lucas and Wolf, I'm sad to see Snake and Ice Climbers go. This means two series' worth of representation are now gone. But if this is the final roster, I'm gonna be more than okay with how this game is turning out.