It won't. This is the only handheld and console release of Smash, I'm sure. Handhelds and Smash just don't work well together.
I think I saw somewhere (don't quote me on this) that Sakurai had intended to bring back every veteran from previous installments this time, though looking at some of the remaining ones, I'm not so sure about that.
But I do think you might be onto something with that. If we are going to bring back more veterans, Wolf and ICies are next in line. Then things get iffy with the remaining 5. We all know the stories of Snake, Ivysaur, and Squirtle, and I don't expect to see Pichu or Young Link back anytime soon. But ya know, we'll see (we got the business man Mario back for who knows what stupid reason).
As for newcomers, there's a lot of popular choices, I could probably name 10 off the top of my head. But, we'll probably only be getting 1 or 2 more. And personally, I'm more hyped for veteran DLC over the newcomers anyway. Heck, I was more hyped for the veterans to return during the entire reveal process of Smash 4 than the newcomers! There's more speculation for which characters will return, and what the reason(s) may be for that character's removal from the series if they're to be cut.
But I honestly think that if Sakurai's thinking about bringing back veterans, he's got ICies on his mind. He was upset about cutting them, and he initially had them in the roster. There will be news on them within the next two Smash events, whether it be in a Nintendo Direct or a Smash focused one. I'm almost positive of that.