X-Men 101: #14 - TIME GIRL

While trying to save Captain Britain from a time anomaly, Rachel Summers was hurled into the far future and became Mother Askani, the leader of a rebellion against Apocalypse. There she brought young Cable to the future, where he'd be trained to fight.
(Excalibur #75, The Adventures of Cyclops and Phoenix #1)

X-Men 101: #13 - WOLVERINE'S KID

Wolverine agreed to take care of a young Japanese girl named Amiko at the request of her dying mother. The girl is presently being watched over by Logan'y ally, Yukio.
(Uncanny X-Men #181)

X-Men 101: #12 - PROFESSOR MAGNETO

When Xavier left Earth with the Shi'ar to heal injuries inflected on him by an anti-mutant mob, he asked Magneto to run the school for him. Magneto did so under the name, Michael Xavier, but eventually left, unable to convince the New Mutants to follow his points-of-view.
(Uncanny X-Men #200, New Mutants #75)

X-Men 101: #11 - BAD GIRL

Before she joined the X-Men, Rogue was a member of Mystiques New Brotherhood of Evil Mutants. She came to Professor X seeking his aid with controlling her powers.
(Avengers Annual #10, Uncanny X-Men #158, #171)

X-Men 101: #10 - CAMERA SHY

After their battle with the Adversary, the X-Men were saved by the celestial being called Roma, who gave the X-Men the ability to not be detected by any mechanical or magical devices. Since then, the ability has faded away.
(Uncanny X-Men #227)

X-Men 101: #9 - ETERNAL BALL

Cannonball once apparently died and returned to life, and was therefore assumed to be an "External," a rare mutant who is able to live forever.
(X-Force #7)

X-Men 101: #8 - HUMAN X-MEN

Some X-Men aren't mutants. Mimic gained his power to duplicate others' powers after accidentally breathing in a strange gas in his father's lab, and Longshot is a genetically engineered humanoid from another dimension.
(Uncanny X-Men #19, Longshot #1-#6)