I'm guessing early next year we will see both Smash Bros. 
Highly unlikely. We are probably not going to see them before late 2014 and more likely in 2015.
Games like that simply don't take 4+ years to make. It's not the sequel to Skyrim.
Regardless it's not going to be out early next year.
I have concerns about screen size. I played a demo of PAS Battle Royale on Vita, and I thought the screen was too small for that, and that's about the size of the XL. I'm going to get it and love it regardless, but it may be my least favorite Smash.
Personally I think Playstation All Stars plays just fine on the Vita. I have no problems with it.
Lol nice copy pasta from My Nintendo News. Anyway, as much as I love Smash Bros, I can't think of anyway this type of game would work on the 3DS. Unless the 3DS version was very limited or just added extra features or something. Idk. Either way, it's cool that it's listed as coming soon. I hope they give more info at E3.
It should work just fine. There was a similar game which also had a sequel both on the DS called Jump Super Stars or something similar based on the Shonen Jump characters and it played just fine.