Honestly I always felt it was a bit weird that people suggested that Dixie couldn't even possibly be a semi-clone. Like not even "she can't be an echo," but "she HAS to be fully unique."
A lot of the movesets I see proposed for her that don't get the "too similar to Diddy" or "just a generic animal" complaints tend to focus on strictly her hair, making her fight more like Guilty Gear's Millia Rage or Marvel's Medusa, but like...her hair is absolutely not long enough to feasibly be used like how those characters do, to the point where that also feels off and out-of-character. Most of Diddy's moves could 100% be kept and make total sense.
One thought I had to bolster her a bit beyond was making Kiddy tag along with her and have
both use techniques based on tag-team attacks as seeb across the entire DKC-franchise.
Still, I've never been against her being a semi-clone, especially when looking at her possible original inclusion attempt with Diddy in Brawl. But that only makes me more baffled on how she hasn't at least been explored as an inclusion to this point, even as an Echo. (As much as I'd hate the latter quite a bit.)
I'm currently pretty confident that by this point, it's just she's been deemed not very interesting on her own at all and also doesn't have much popularity to warrant an inclusion as an Echo or semi-clone up to this point. But I digress.
I think at best I'd imagine Dixie could have her ponytail be used to slightly higher range than Diddy's limbs to change good bit of her normals. Maybe Monkey Flip would be changed to a pony-tail based command and bolster her being a more aerially proficient fighter with some grappler moves like you wrote.
Sakurai might have something against Takamaru. Initially he dismissed Takamaru for not being known outside Japan. No one really knew who Mr. Game & Watch was. Smash always introduced a near forgotten retro addition. I just find Sakurai's reasoning strange and interesting.
Honestly I feel this going to C-Listers as a whole seems to only add more on them being on a constant lose-lose situation: Sakurai already deeming them too obscure will just keep them that way because Nintendo and their 2nd party companies themselves won't (or can't) bother with them any further beyond. Some revivals get being attempted but they really hinge at the original crew being around, which worked best for Famicom Detective Club, not so well for Advance Wars.
For as long as we've followed the series with these characters, haven't had new game for years and already not really being much for Nintendo to explore thinking of throwing in among their mainstream/new IP additions (Takamaru) - or if they got a new game, they get glossed over anyway due not interesting Sakurai in means of moveset on top of being from C-Tier IP anyway. (Isaac).
The only guy getting past this both ways so far has been Little Mac in Smash 4, thanks to Punch-Out Wii + Sakurai getting interested on Mac mainly due wanting to take how he functioned as an Assist Trophy in Brawl and turned to a full-blown character.
It's kinda annoys me as Smash would clearly rise any "dying" or "too obscure" IPs from such pits of irrelevancy due being introduced to millions of new fans, as we got to see with Fire Emblem (twice), and with Xenoblade Chronicles.
Kid Icarus to lesser extent as Uprising did heavy lifting anyway. It's really what I wish Smash capitalized a bit more on since it introducing me to many IPs I didn't know before that had come to be my faves since.
It's why I've been wishing for the protags of such series being relegated to Assist Trophies, to get overhauled to be more integral part of the game
through a partner system as I had discussed before. It'd make them at least become more notable part of Smash enough to help she more spotlight on these series without having to explore them with playable characters over the on-going relevant picks from newer IPs or installments of existing franchises.
Best shot they have as these summonable NPCs anyway, incase Isaac was brought back as an AT by popular request from the ballot. 