I doubt any of those characters would be in Smash. Mortal Kombat and Danganronpa are way too brutal (and the latter is pretty obscure). Sam & Max is full of mature humour and euphemisms, I somehow doubt Nintendo would want that. And I don't really consider the pair to be fitting otherwise, since they're comic characters, rather than video game characters. The only franchise I can remotely see is Elder Scrolls but... I dunno, it would feel -wrong- to me.
I feel like Bayonetta is the furthest we're gonna go in terms of maturity for both violence and sex (and she's just very sexy; Sam & Max has jokes like "Prison showers. Man if these walls could talk." "I think it's better if they'd keep their mouth shut.").
I dunno, Bayonetta goes p-r-e-t-t-y far. Her torture attack (Also, again, "Torture Attack") for Joys is a barbaric, sexual bisection device that Bayo personally binds/pushes the Joys into. And IIRC, she also individually binds their breasts. Really, anything and everything about the Joys should have been more than enough to keep her out. And yet somehow, she's in a video game alongside Villager and Kirby.
Meanwhile, we have proof Scorpion/Sam & Max can be toned down: they both had Saturday morning cartoons in the 90s. The S&M one even captured the comics'/games' tone pretty well with a Y7 rating! And just like Bayo, we wouldn't see DanganRonpa executions in gameplay. Hell, they can throw in Travis Touchdown (Or maybe Shinobu; Grasshopper was on that list so maybe that Shinobu-led NMH3 is happening?), and a 4-way match between them will still feel like Smash... So long as you forget about their origins (Just like Snake & Bayo!).
Again, I'm only thinking these guys because of that list of Switch supporters (People didn't find Jade a weird suggestion after the BG&E2 rumors, right?), but who else would these companies add if they got involved with Smash? Would WB & TellTale join forces and share Batman? (Fake Edit: Oh, Spike Chunsoft was involved with Fossil Fighters?)
*Remembers Activision (which I'll assume includes Blizzard) is a listed development partner*
Not that it's likely, but I wonder how people would feel about Mei from Overwatch entering Smash. She's not the face of Overwatch -- that'd be Tracer --, but I figure Mei's the more memorable of the two for all the times she's slowly inserted icicles into people's eye sockets. More importantly, creating platforms and barriers is an underutilized concept in a platform fighter and I figure Mei can bring something new to Smash in that regard. At the very least, I see her being a fun doubles character, walling people out, creating additional platforms to jump/up-air chain off of, saving teammates about to fall to their death by giving them something to land on, etc. through ice walls alone.
Hey, hey! I'm not the craziest one here anymore! That said, with Blizzard avoiding Nintendo and with Sony trying to push Crash, an Activision rep would almost certainly mean...
Skylander Spyro is a possibility, however remote, and is a beautiful idea in a monkey paw sort of way.
Sakurai fought to get us Classic Pac-Man when Namco pushed for Cartoon Pac-Man, didn't he? Plus Bayo & Cloud got special Alt. treatments. Maybe Good Spyro could be a costume?
I'm surprised that Excitebike assist trophy was removed from Smash 4.
That really surprised me, too. Sakurai seemed to love pushing Excite Bike/Mach Rider in Melee/Brawl. I wonder what happened?