Aside from the Puff(who's in due to veterancy), I doubt any of the other 'possible veterans' are coming back, and aside from Chrom, I really don't see those newcomers happening. Fan-favorites, well, when has Sakurai paid much attention to that aside from maybe giving them a larger space on the dartboard he uses to decide on characters?
At this point, I wouldn't even count on Puff and the O12 veterancy to be relevant. Little Mac's neutral-B easily replaces Falcon Punch in both utility and power, and he moves at about the same speed. I could see Puff, Falcon, Ness and G&W at-risk, if not gone already.