Honestly, I'm a bit skeptical of Daisy's chances, if she hasn't made it before... Still, I'm dropping in to say I'm rooting for you guys.
In all honestly, Daisy has slowly been getting individualized, but at this point, someone has to step in, give a hard look at Daisy over all her appearances and start putting together a detailed lore around her and her neck of the world based on things to present to Miyamoto before anything can really happen, I feel. At this point, I think Daisy is more than capable of rescuing herself, so I can easily imagine a reverse Mario game happening here. Daisy breaking out of wherever she's taken to after being ambushed and working her way home, using all the skills and quirks she's picked up over the years. This is the kind of push she needs.
As for Smash, I've been seeing the conversations about alts vs. clones. You're right in that a lot of her specialties are quite different from Peach so full on Alt. Costume would only do her injustice. I can see a few moves being similar, just using native power-ups from her home like the Superball and the Carrot power-up. Heck, she could use the Superball like a shield before tossing it back at the offending fighter, as an example, but for the most part, just taking her specials from the different sports games would be enough to give her a faithful moveset. It's an all or nothing situation for her, I think so... That's my thoughts.