Saying Ganondorf's Moblin Ganon form(as in the bipedal version) is in Smash isn't even up for debate. It's literally not in there. His Beast Form from TP is. Puppet Ganon is too in some way, as a Trophy. There are 3 literal forms of Ganon. One is nothing more than a short transformation attack. It is not actually treated as a remote character in the files either, as you cannot directly play as it in either game like you could certain transformation characters(Giga Bowser, Super Sonic, Wario-Man, who all have actual ability to be played as). You could replace it with him using his Dead Man's Volley or King Bulbin running down the opponent with the same overall result and the impact would be the same in how "important" this so-called transformation is. It's actually sad they dumbed down one of his best and unique forms to a weak cutscene, despite it actually being a real boss fight.
Again, that's like saying we can't have two separately playable Links. But we do. Each game but Smash 64. One version of Ganon(with a special name no less to separate it from Ganon's 3 very distinct versions, so people didn't confuse it with the actual iconic Ganon version, which has always held the Moblin Design, even to the point that he didn't have an immensely large size till a Moblin finally did. He was always bigger than Moblins, but usually not by a severe amount. WW subverted that finally, but then again, he used Puppet Ganon, not the regular Bipedal form, which again, is the iconic version of Ganon people clearly want playable.)
As much as I want Tingle, he's not really likely to happen. It has jack all to do with his AT status(which he obviously got due to being a very notable character, quite a lot of popularity through 2/3 of the world(UK and Asian countries. He was only unpopular in the US regions... which has changed as well over the years), it's the popularity issue first. He's absolutely the most notable after the main 10(Link, Young Link, Toon Link, Zelda, Sheik, Ganondorf, Moblin Ganon, Toon Zelda, Tetra, Toon Ganondorf), being he's the only Zelda character to earn himself more games. That cannot be denied when it comes to notability.
Impa is more prominent now, but she didn't gain real notoriety till SS and later HW. She is a viable candidate, and clearly has multiple moves to draw from among her games. Ones very unique from Sheik. Sheik's moveset is more or less an original one that bar her Up B and Down B in Melee/Brawl, didn't come from a game at all.
Tetra is way more likely than Toon Zelda being she actually has unique properties to take from now. Toon Zelda(and a similar counterpart planned as Toon Sheik, at least, again, the plan, since the actual data files explicitly has that and no other name) was at one time planned for Brawl, clearly as clones. While I'd imagine Tetra would replace the Toon Sheik idea due to being easier to make a unique moveset for, it actually is easier to make Toon Sheik due to simply being a clone. Being Sakurai made Giga Bowser with an actual proper Smash moveset, there's really nothing to suggest he would care if they're a canon character or not(the fact he's even remotely playable without a cheat device, even if a short period of time, further cements the idea that yes, he could make an OC playable if he want to. Keeping in mind that the Mii Fighters come from the Smash Universe, and Captain Falcon's moveset uses a full outside source of inspiration, namely Japanese Superheroes, like Kamen Rider, he doesn't really really care if everything is canon. There's always more to it than that). Should go without saying I'd have preferred Tetra, but the idea that he couldn't make a Toon Sheik is pretty easy to debunk until we have evidence(like his own statement and no way to play as OC characters(hi, Giga Bowser). The only evidence is among 7 files for playable characters. 6 are clear as day who they meant. 1 is not(Pra_Mai).
Likewise, Ganon is absolutely not even remotely and properly represented in his iconic form in any way. Not even a Trophy or a Sticker. Let's stop pretending his iconic form is in the game and being he has a legit design that could make for a character, cannot be a possible choice. There are many reasons he could not be in. For instance, maybe his best window was Melee when OOT was shown off, and we know they only had enough time for a bunch of clones. Maybe Sakurai doesn't want any more playable Zelda characters(he really does like Ganondorf and his old moveset, after all). Maybe he doesn't like the idea of Ganon and Ganondorf having a weapon as a key part of their movesets. Nobody knows. Doesn't mean Ganondorf iconic transformation exists in Smash. Just quick and small cameos of his other two forms of Ganon that don't have much prominence in the Zelda series as a whole.