Smashboards

Well I wouldnt exactly say she was most likely seeing how she isnt a video game character, just had cameos but it would be a pretty cute Smash Character lol

i said most likely NON-GAME character

I'd say the most likely non-game character to get in Smash would be either Goku (because of fan demand) or Popeye (because of relevance to Nintendo)

Wario Wario Wario well i'd also argue Hello Kitty because of the sheer amount of in-smash franchises she's already crossed over with or Scrooge McDuck because the NES Ducktales game was a standout of the console

Also, Popeye will be entering public domain at some point, so that'd make it easier (yes, I know he currently has a comic deal, but that's besides the point).

Disney is very picky on what media their characters can appear in. I heavily doubt they'd give the OK to Scrooge McDuck fighting alongside Bayonetta and Solid Snake - especially since McDuck rivals Mickey in popularity in some areas of Europe. in fact, there are unused files for a Shantae crossover in DuckTales Remastered, and while there's no info on whether it was rejected by Disney or WayForward, it seems likely that Disney weren't keen with Scrooge McDuck going on an adventure with a genie in a bikini. I'd also reccomend watching MatPat's Game Theory on the Frozen world in Kingdom Hearts 3. even through most Game Theory videos are utter rubbish, the Kingdom Hearts 3 theory actually makes a lot of sense.

HK is a more interesting case. Sanrio are no strangers to violent crossovers - franchises like Gundam and Godzilla are particularly notable - but while I could see Sanrio being on board, I can't see Sakurai being on board - since Kitty isn't particularly violent, and of course that didn't stop Villager or Wii Fit Trainer, but the difference is, there are no "4th party" characters in Smash yet, and Kitty White would be an awful introduction for "4th party" characters (yes, I know that from a legal standpoint there's no such thing as a "4th party", that's simply the name Smash fans have accepted so I'm rolling with it) given that she's probably in even less demand than Piranha Plant and WFT were.

also, HK having crossed over with Sonic and Mario before means nothing. remember Shaun the Sheep in Mario Maker? the Sonic and Garfield Pack? SpongeBob and Transformers in Splatoon?

Wario Wario Wario HK has also crossed over with Animal Crossing, Monster Hunter, and PAC-MAN

Adding to that, Disney fights tooth and nail so that Mickey Mouse's rights don't end up in the public domain, so yeah...