Here are some notes about these characters, for reference, too. You can click to view on Comic Vine which may have more info...

* Keep in mind that had Disney kept them, they probably would all be much younger and more child friendly.
* These characters do not appear because they are owned by 20th Century Fox, who created the current 'X-men' films (the most recent one is 'X-men: Days of Future Past)
* They are all mutants except Sunpyre, who is an alien princess.
* Kenuichio is not an actual Japanese name. I don't think 'Kioshi Keishicho' is, either.

link
* There are TWO Sunpyres (only the one who didn't join Big Hero 6 is Sunfire's sister)
* The one that joins Big Hero 6 is Princess Lumina from a planet called Coronar. She came out of Honey's power purse (in this version, it has dimension portals that let her pull out nearly anything) and because of that, she worships Honey as a goddess (LOL). She later left the team to go home and reclaim her throne with Ebon Samurai's help.
* The Lumina Sunpyre is not a mutant, but has her powers because she's from another planet. She can fly, can shoot plasma blasts, can manipulate heat and is immune to radiation.


link
* His a mutant, can fly, blast plasma (the same thing Wasabi's knives are made out of), has infrared vision, and is immune to radiation.

link
* Silver Samurai was evil and a criminal at various points in time. I'd say he's actually more bad than good.
* He is a mutant, his power is "channeling energy" into his katana/sword (making it able to cut anything) and teleportation
* He is the only character 20th Century Fox has actually used so far, in 2013's 'The Wolverine'. He actually appeared as two characters with different names, a member of the 'Black Ninja Clan' sworn to protect the family of the other Silver Samurai; the other is a very, very old man who is determined to live forever, which tries to do by making a giant metal suit --- a silver samurai suit. He is the main villain of the film.

link
* He is undead (zombie, basically) and master swordsman.
* His sword is apparently bound to some demon (unseen) that charges his blade with dark energy.
* Was created by comic writers to replace Silver Samurai, who left BH6.

Either Sunsfire or Silver Samurai. But I vote for Sunfire because he is Hiro's idol in the comic ^_^ As for Silver Samurai (Harada), I kinda adore him in The Wolverine that's why I would love to see him in other version XD

Despite my strong love for Silver Samurai, I think Sunpyre would be the coolest to have because her powers are easy to adapt to technology and it'd be funny to see how Disney would adapt Lumina worshipping Honey as a powerful deity, lol.

My ultimate dream, though is to have Sunfire, and for him to be Tadashi, because it seems like a perfect fit for Tadashi to mysteriously survive because he has some sort of power/techology (the way he dies fits). He could have stayed hidden for some reason or other, I dunno, Marvel is good with total nonsense "He survived" stories like that, haha.

I heard that in the sequel Tadashi's Sunfire

I guess so