I'll start with the positives and go on to the negatives
You have a wide variety of deserving and potential characters and worthwhile additions. I like the addition of Roy over Chrom as he seems to be more popular, requested, and iconic, had an addition in Smash before, brings a bit more variety than Chrom, and had a prequel starring his direct and identical relative who was the first American Fire Emblem protagonist. I too agree that Dixie Kong will get in over King K. Rool for some reasons so good job there. I agree Sukapon should get in, but Sakurai specifically told us not to expect him. I'm also flattered you liked my Mii icon idea, I had Ariand/AEM make it. Also I think an F-Zero rep is a good idea, but really don't think it will happen.
Now for the negatives:
I have to ask about Geno. You say he has pre-Brawl popularity. I don't see how this warrants an inclusion. He's an obscure one-off character who only had one fairly significant role in the Mario universe. I understand Sakurai acknowledges fan requests, but you still need more than that to get in. All the fan requests added in Smash were incredibly deserving and fitting characters. I don't see the positives or motives of adding Genon and if I'm correct, Nintendo doesn't even own the rights to him anymore. I don't understand how he'd get in over Bowser Jr or the protagonist of the successor to Mario RPGs: Paper Mario. 6 Mario characters isn't going to happen either, I'm skeptical that we will even get 5.
Toad.....it's just not happening. If Sakurai plans the roster before development it really wouldn't make sense for him to have a character be used as a human shield towards the same character especially when he's revamping so many move sets.
Sukapon would be plausible if Sakurai hadn't specifically told us not to expect him.
I think Ninten is the only reason a third Mother rep would be added as it's perfectly fine at 2.
Tingle is a plausible Zelda character, but since Zelda is repped perfectly fine I feel he wouldn't fit in or balance out the representation or that Zelda even needs a fifth character.
In conclusion, it's a fun roster, but it seems rather large and has a few questionable characters.
Geno: I put him in for safety, although it's mostly selfish on my part, as is Porky.
Toad: I'm not going to make a big deal out of this. I still hope the guy's in, as Blue Toad or whatever, and it's been shown that there can be more than 1 Toad with a blue vest and red spots. However, I'll agree with you on this one, but I will say that if I were to choose another character, it'd be Paper Mario. But I still feel Toad's more deserving. In fact, I'm thinking about replacing Geno with Paper Mario to rep his own series (Mario RPGs).
Sukapon: The whole Sukapon inclusion was also based off Villager being dismissed from Brawl, yet appearing in SSB4. So, a small part of me hopes Sukapon will be the revived retro character, since Sakurai's changed his mind about other things too.
Porky: A bit of selfishness on my part, I just love the character. Ninten would be great with me too, as would Masked Man/Claus, but I definitely think that we won't get another Mother character, it's just hope on my part.
Tingle: I feel that, while Zelda is repped well, I included Tingle to round out the Top 3. Since I gave Mario 5 characters (Geno counted as his own series in my head), and Pokemon 5, I gave Zelda 5. I figured Tingle is the one of the few truly iconic characters left not to be included in Super Smash Bros as a playable character (besides Toad, Ridley, Dixie Kong and Little Mac), and I didn't really see too much potential in other Zelda characters (Skull Kid was irrelevant by now even though I like the character, Midna and other Twilight Princess characters had their chance in Brawl, Ghirahim isn't very likely at all, Impa seemed redundant with both Zelda and Sheik already on the roster, Toon Zelda w/Tetra felt weird having over half of the roster being versions of the same characters in different timelines and Groose or King Harkinian aren't going to be in for sure.) Besides, since Balloon Fighter seems unlikely with Villager, I want to see at least one character with balloon-centered gameplay.
Dixie Kong: I'm a BIG King K. Rool supporter, but recently, I haven't been feeling so good about him. I feel that with Dixie Kong's revival, we might not see the good Kremling Kaptain for a while.
Roy: He and Mewtwo were added because they're the two veterans everyone wants to see come back. Nobody seems to care about Dr. Mario, Pichu or Young Link, just these two. And, because I'm a pyromaniac, I love Roy too, so I added him in.
Mii: That was the Mii icon you suggested? Wow, small world! I prefer it over the bland, generic "Mii" button, or the default Mii because it feel like you can select your Mii and it'll pop up there instead. It's a novel idea, and I prefer it over anything else.
Only now have I noticed it's a 57-man roster (including ZSS, Sheik and the Pokemon), which is pretty big. I also planned on having Waddle Dee and Lip from Panel de Pon at one point, but I decided against it for a smaller roster.