The Members of Boys Sensation:
Aidan Emory (later Aidan Emory-Decker)
Aidan is, for all intents and purposes, the main character of Boys Sensation, if I had to pick just one. He's the one that a lot of the events of the canon revolve around, and he's the breakout star of Boys Sensation. He starts out as selfish, egotistical, and a perfectionist. He originally wants to do everything on his own, wants to eventually break free of the group bind and make it as a solo artist (and therefore fakes his friendliness toward Dylan and Nic), but a talk deflates his ego and he realizes what's more important, and grows really close with Dylan and Nic. He's gay (his sexuality is the driving force of most of canon), and ends up with Luke, with them marrying toward the end of the main canon. Has one son, Hunter, with good friend Elena Jones-Hale.
Lucas "Luke" Decker (later Lucas Decker-Emory)
Luke is Aidan's best friend, and the one who initially informs Aidan of the talent contest for Boys Sensation. They met after Luke's parents divorced and his mother moved him and his five sisters to California. Luke is a victim of child molestation (by his father), and because of it is doubly apprehensive about his sexuality and feelings for Aidan (he worries people will think being molested by his father turned him gay, and that in turn makes him wonder if it's true). Ends up with Aidan, and has one son, Channing, with friend Leilani Hale-Jones.
Dylan Newman
Dylan met Aidan and Luke during the auditions for Boys Sensation, they were in the same audition group. He's an only child who lost his father at a young age (and his uncle, who was a father figure to him, in the course of canon), and he has a hard time coming to terms with both deaths and why they had to be taken from him. He's also highly jealous of Nic at first, because he feels Nic is just better than him at everything. Is Nic's stepbrother. Starts dating Tanya around the time of their second album, and eventually marries her. They have twins, a son named David (named after his father) and a daughter named Melody.
Nicholas "Nic" Atwater
The oldest member of Boys Sensation, he tries to use that to his advantage and impart wisdom and advice onto the others (Dylan and Luke take it, Aidan tries to fight it). He does, however, have a wild side, as he's the one to take Aidan out for drinking and clubbing on his 21st birthday. Discovers he has a talent for songwriting during the Boys Sensation/Backstreet Boys duet, and ends up becoming the group's main songwriter. Has two girlfriends over the course of canon: Amanda (who is deaf), and Grace (who he eventually marries). He has one daughter, Aimee, and one son, Kristofer, with Grace.
Other Important Characters:
Joe Jones
The creator of Boys Sensation, and the group's first manager. He is, for lack of a better term, an asshole. He is all about the money, and his reasoning for where he gets that money is flawed. He doesn't trust the boys and thinks every decision they make is bad, and every one he makes is in the best interests of the group. He is also slightly homophobic, specifically saying that the boys can date, as long as they date women, thus keeping Aidan and Luke in the closet for way longer than they intended. Is eventually dropped by Boys Sensation.
Elena Jones-Hale and Leilani Hale-Jones
Members of girl group Sparkle, whom opened for Boys Sensation on one of their tours. They are a lesbian couple, and are enlisted by Aidan and Luke to have children with them. Elena has Hunter with Aidan, and Leilani has Channing with Luke.
Julie Decker
Luke's oldest sister. She is in love with all things boy bands, and most of everything the members of Boys Sensation know about them (especially their direct predecessors from the 90's crop of pop acts) comes from Julie.
Other bios (other family members, children, etc.) forthcoming.