I find it weird that you think Mike Jones and Andy aren't viable but Diskun and Sheriff are. On the third party front you're sleeping on Heihachi's as well.?
A lot of those I named off the top of my head. Startropics and Advance Wars are still nintendo series and are viable to be in Smash. Mike Jones could have an awesome moveset imo. I kinda kept Heihachi off because Sakurai commented that he considered him but eventually went with Ryu over him. I have a feeling Heihachi, or the Virtua Fighters, or Nightmare, or any of the other fighting game giants won't get in because we already have the king of fighting games in. I mean think about the 3rd parties already in:
Ryu: King of fighting games
Cloud: King of JRPGs
Megaman: King of sidescrolling shooters.
Snake: King of stealth games.
Pacman: Father of video games.
Sonic: THE biggest rival to Mario and Nintendo.
The only exception so far has been Bayonetta and she got in because of marketing, scoring decently high on the ballot, and that shes pretty much a psuedo 1st party now.
The only archetypes of characters I can see getting with no hurdles at this point are legendary mascot characters like Crash, Rayman, Spyro, Bomberman or Banjo.
Other 3rd parties left would have to represent their genre. Like for example, a Dark Souls rep probably won't get in when a Monster Hunter seems more iconic to Nintendo. Both are similar genres of games so I don't see both.
We do need a 1st person shooter rep, and while Masterchief and Doom Guy come to mind, we know Sakurais stances on real guns and he'd probably stay away from them to avoid an unnecessary rating.