*Membership spots not really limited!
Knowing the dangers of magic and resurrection, the invaders have found a realm without magic, which they use as a prison world. They brainwash and hide the captives away on this world, along with guards to keep an eye on them. Most are well-hidden in Earth and can not be found to be reawakened. Others know who they are but do not want to leave their new life. Others still have found something worth fighting for, become a better person, or simply want to return to their old lives. But, either way, they're willing to fight the invaders.
And the guards, although working with the invaders, certainly have their own hidden agendas (which probably led to them getting "awarded" with this station). The lack of oversight and the feeling of abandonment they all seem to share only adds fuel to this fire.
But the invaders don't know that, as more magic enters the realm, the brainwashing is fading for a select few (most of them were placed into alternate identities that mirror their "real selves" in some aspect, so that they would readily buy into their new life) and objects of power are being drawn into the world.
(So it's like "Fabletown"/"Once Upon A Time" on Earth and "Ready, Player One" in the world of video game, with a little "Neverending Story" thrown in.)
Samus Aran, Simon Belmont, Dirk the Daring, Edward Kenway,
The Great Rebellion
Fox McCloud, Index Librorum Prohibitorum, Link
The Evil Empire
Mishima Zaibatsu Corp.
Carmen Santiago (more of a free agent), Heihachi Mishima, Jack series, Kazuya Mishima
Samus is a bounty hunter on Earth. But we'd get to see scenes of her in her armor (flashbacks, off world action down the line, etc) at some point.
Simon would be a monster hunter, pretty much like Dean Winchester
Carmen Santiago? Think Sherlock's take on Irene Adler. C.C. Rendozo from Wildcats 3.0. Zoe & Root from Person of Interest. Or, y'know, Carmen Santiago.
As for Dirk the Daring... you remember how, in the cartoon, he could see all of the different options in front of him? Maybe he's got his own limited "Sherlock Scan"or whatnot...
Fox McCloud's my Top Gun, my Luke Skywalker piloting an X-Wing, shooting down the Death Star.
Ganon's tower would be full of artifacts/obstacles from other, familiar games, like the Fire Swords, spikes, deadly fog (which I THOUGHT I could use as my "F" pick), etc.
Imagine the Mishima Zaibatsu Corp. as "Wolfram & Hart" and Heihachi's the current CEO.
Index is basically The Archive, with 103,000 grimores in her head.
Jacks are pretty T-1000 series Terminators (the Arnold Schwarzenegger model), but Russian.
Kazuya's basically Smallville's Lex Luthor, but with the Devil Gene.
Link's the epic, optimistic hero. Like Luke fighting Darth Vader.