Nightcrawler
Conceived by Dave Cockrum in 1973,as a spin-off of DC's "Legion of Super Heroes" and rejected by then editor Murray Boltinoff, The "Outsiders" counted the protoypic Nightcrawler among their number. Undaunted, Dave suggested the character as a member of the New X-Men team during the initial development conferences.
Claremont's plans for Nightcrawler's history were originally to have Mystique be his father, and Destiny, his mother. This idea was shot down quickly by Marvel editors, however, as it was far too controversial.
Phoenix (Jean Grey)
It was never the writers intention to kill off Dark Phoenix/Jean Grey. Her penance for killing a planetful of lives was to be the loss of ALL her powers, including her telepathy and telekinesis, which preceded the Phoenix's presence, then marry her off to Cyclops and have her become a background character. But Jim Shooter, the then Editor-In-Chief, declared that Phoenix must die for her crimes. And so it was that the legendary issue 137 was written.
Jean has always had an incredible attraction to Wolverine, resulting in at least 3 on panel kisses.
Rogue
When Rogue was first created, she was meant to be a mutant in her early to mid-forties! According to Claremont, she just got younger and younger as time went on
Once, when her Carol Danvers persona was dominant, Rogue touched Psylocke skin to skin without absorbing her psyche and powers! But if Carol Danvers knew the secret of controlling Rogue's power, it was lost forver when the two were seperated by the Siege Perilous and Carol Danvers died.
Once, when Rogue retreated to the furthest depths of her subconscious, she found ghosts of all the people whose powers and memories she'd ever absorbed, sort of a residual psychic energy of each individual. Among them were Juggernaut, almost all of the X-Men, Thing, Spiral, Northstar and even Thor and Captain America!
Storm
The orginal design for a character called "Black Cat" by Dave Cockrum, was a proposed member of the second generation of X-Men but didn't make the final cut. At the suggestion of Len Wein and Roy Thomas, her costume design and race were combined with the powers of another character (alternately named Typhoon and Tempest) to create Storm.
As a rsult of being buried benaeth the rubble of a building as a child, Storm is extremely claustrophobic.
Wolverine
Wolverine has a son which he is unaware of, sired during "The Jungle Adventure" with a native woman from the Tribe of Fire.