Okay, here are the most likely character reveals for this week: Ice Climbers, Wario, Falco, Mr. Game & Watch, and maybe Jigglypuff.
Near the tail end of the month, we can also include Ness in that roster due to the Earthbound Anniversary (even though Lucario was the only character to date whose reveal coincided with an anniversary).
So why these five characters specifically? Well, Ice Climbers due to a leaked in-game image that shows them performing their side taunt in battle against Little Mac, Rosalina, and Greninja on the Mushroom Kingdom U stage; the fact that such a battle was recorded off the Wii U gamepad (which may deconfirm the leak if gamepad-exclusive gameplay isn't possible); and the fact that there was no viable live feed of such a battle between these three on that very stage that could be adequately photoshopped. Even disregarding the leak, it always felt appropriate and likely for them to be the next character revealed.
Mr. Game & Watch, I feel could very likely be our next reveal since he was teased at E3's Pac-Man trailer. But, if his teased appearance is to build up to something else (like my theory regarding Jigglypuff or R.O.B. being teased in order to build up to the unveiling of the Chorus Kids), we may not even get official confirmation until after launch.
Falco mostly draws from the now debunked Petilil leak, but there are several reasons why he is very likely to be revealed next. For starters, we have yet to get any Star Fox-related stages, and Fox is the only initial 10 veterans not to have another character from his own franchise revealed yet. The fact that Luigi, Toon Link, Marth, Sonic, and Lucario were all revealed before launch even though they were all historically unlockable characters, with all but Lucario having so far, been suggested to be starters in some capacity or another also helps his case, arguably moreso than any other unlockable characters. With the exception of Pac-Man, I believe all the characters revealed so far will be a starter in at least one of the two versions of the game (a few may even be version-exclusive starters, mind you, where you have to unlock them in the other version), and I believe this trend will continue on until Japanese launch. On top of that, this is the second straight day where Sakurai's pic of the day turned out to be connected to long-range smash attacks, which may in fact, build up to a character and/or stage reveal to round up the week. So, if we don't get Ice Climbers, Falco is my next most likely pick.
Wario: So far, Captain Falcon, Ness, Lucas, and Meta Knight are the only other characters left who have had experiences as starter characters who are likely to return. Ness and Lucas will be tied more to Earthbound's anniversary more than anything (with Lucas likely to be cut), while Captain Falcon and Meta Knight comes across as characters that will wind up being unlockable content this time around. This essentially leaves Wario as the most likely returning veteran not named Falco or Ice Climbers to join the roster this week. If the week passes, this might change down the line, but for the time being, I do believe that we will be getting Wario fairly soon.
Jigglypuff: I might be splitting hairs, but she is essentially the only character left of the original 12 who has never started in a Smash Brothers game; Luigi is highly likely to be doing so on the 3DS, and Ness and Captain Falcon have all done so in Melee. I know I mentioned the leaked reveal last week or something, but the fact that Kirbopher was interviewed by GameXplain, and no mention of Jigglypuff being leaked was made leads me to believe that the person who dropped the bombshell really just made a big mistake. Still, I find her far more likely than any of the other veterans on standbye except maybe Meta Knight--who I predict to be an August reveal at best.
Speaking of which, for August, I'd cut Jigglypuff and Mr. Game & Watch from my considerations, and add Meta Knight (his would be a very special reveal) and Ganondorf (Hyrule Warriors release) alongside Ice Climbers, Falco, and Wario. Chances are very great that we'll get one, if not two of these three this month. As for newcomer reveals, there are five possibilities, and it all depends on what kind of Direct it will be, and what Sakurai has planned for August as a result. Here they are:
Mewtwo: While not a newcomer per se, the fact that he was absent in Brawl will more than likely suggest that he'll get a newcomer trailer. This is assuming that Jigglypuff gets confirmed beforehand, or is otherwise to be teased again (similar to Mr. Game & Watch to Pac-Man), and will likely only happen if the August Direct turns up to be a Pokémon Direct.
Shulk: They may choose to reveal him only if we begin to see a steady amount of hints building up to his reveal. So far, the only piece of evidence that is in any way, shape or form, concrete, is the fact that his voice actor came out and stated that he just got done voicing characters for games coming out this year, and will tell us about them once he knows he won't get in serious trouble for doing so. It was rumored that some people found some Mechon M60 trophies; I actually want to see those trophies. Very unlikely regardless, because he just screams secret character to me.
Chrom: What this guy has going for him is the version-exclusive STARTER theory. If either Shulk or Chrom gets revealed, it'll probably tease R.O.B.; Shulk's trailer would probably have him fighting R.O.B. in much the same way he fought the Mechon, while Chrom could join Marth and Ike in a trailer paying homage to Brawl's SSE.
Chorus Kids: Really, R.O.B. and Jigglypuff have to both be teased--if not flat-out revealed--before Chorus Kids can make any sense. They'd work best as character reveals after launch.
Ridley: At first, I thought his chances were going to be likely due to the release of Smash 4 this September, but let's be honest; if he is to be playable, he'd be revealed either in October, or around the time the Wii U version comes out. Pyrosphere is a Wii U-exclusive stage, anyways.
So, the characters I feel are most likely to be confirmed next: Ice Climbers, Falco, and Wario. Ness might come afterwards, but the remaining two will have a more likely shot at getting in. And then in August, I'd add Meta Knight over Ganondorf due to how special a moment it would be, and it would help build a lot more hype without taking away from the other characters. In the Direct, it all depends on what is being planned, but for now, Chrom is the most likely option.