Tommy is a product of Wiccan's powers. Wiccan's powers are a product of Scarlet Witch's powers. None of the above individuals are related.It's one of the directions I see Children's Crusade going. Billy and Tommy discover that they aren't really Wanda Maximoff's sons; Billy's powers were granted to him by Scarlet Witch's reality warping when she ran into him outside the Avengers mansion; and Tommy was created by Billy's reality warping to make his belief that he is Scarlet Witch's son (a.k.a. The Ultimate Fanboy Delusion) sound more plausible.
Billy IS the Scarlet Witch.During Children's Crusade Billy will discover that his whole life, his family, his powers, his unrelated speedster twin, were all created by Wanda as a place to hide after House of M. The situation will devolve into "Ben-and-Glory"-style antics before being resolved in a satisfactory and/or heartbreaking fashion.
Teddy didn't exist until Genis-Vell recreated the universe.During Peter David's Captain Marvel series, the title character (Genis-Vell) tore down and rebuilt the universe with one major change—he now had a sister, Phyla. Given Genis' desire for a family, he could have subconsciously created Teddy, or perhaps have manipulated the events which led to Teddy's birth.
Scarlet Witch and Rebecca Kaplan will meet...And get along great (while Billy panics outside whatever room they're in). Plus, Tommy clearly needs more supervision than Billy, so that will take a lot more of Wanda's time. They work out that Rebecca is in charge of civilian Billy and Wanda is in charge when he's doing superhero stuff. There will be hugging.
Billy is a Germanophile
Hulk is Billy and Teddy's kid.
There will be an alternate time line where...
There WILL be a Wicked reference at some point.
Billy will Geek Out over Kid!LokiAfter all, he showed an immense interest in Norse Mythology and he'll probably also bond over having another magic-user on the team with him.
The reason why Tommy isn't in the new Young Avengers volume...
Loki will become Billy's Big Brother MentorLoki will realize Billy's potential and try to groom him as a servant/paun at his disposal by mentoring him in magic, only to reluctantly become fond of Billy and genuinely try to help him grow out of being a Woobie, Destroyer of Worlds.
To go with the above, the Young Avengers will become Loki's Morality PetsLoki will slowly Become the Mask of the "mischevious and lovable godling" and might even perform a real, if reluctant, Heel-Face Turn. After all, he wouldn't be the first Avenger to do so!
Kid Loki is still a kidNot Kid kid Loki, but a child Loki from another dimension entirely (maybe the one we saw in Vengeance?).
Cassie will come back - evilOr at least a version of her. The end of Children's Crusade is pretty implicitly Iron Lad's Start of Darkness, after all, and he clearly has a somewhat obsessive thing for Cassie. Combine that with the fact he's never had any compunctions about screwing around with the timeline (as noble as his intentions were at first), and I absolutely expect to see him pop up with a dark version of her at some point in the future.
The Crossover theoriesGillen said that there is only one place in his planned run, where he might do a crossover between this series and another one - around issues #13 and #14. Which means that, unless it's going to be a crossover with Avengers Arena (which will, coincidentally, ending around the same time), Mother plotline will be solved since then or in crossover, because, considering her spell preventing adults from noticing these kids have a problem to solve, it would be hard to cross the series with anything else.
Kid Loki will regain his body with help from Billy's magicIn the Siege event, Loki was revealed to be impersonating Scarlet Witch because of a spell from Billy. His magic/reality browsing ability can be manipulated into revealing that Loki has Grand Theft Me his younger self and giving the younger self control again.
Billy go on a Roaring Rampage of Revenge because of Tommy's kidnappingRemember that Teddy being in trouble made him knock out an entire terrorist cell by accident. Tommy being in trouble will give Billy a chance to show his Big Brother Instinct for once.
Cliffhanger from issue #8 is a Secret Test of CharacterWhile I don't mind David being gay or bi I think here he is just trying to make Hulkling get over his doubts about his love for Billy. If there is one place where subconscious spell should stop working is dimensions apart from it's source and in the lair or being who can block that magic. Teddy will freak out because he cannot be unfaithful to Billy and David will point out that means his love is true.
Loki will end up controlled by the MotherThey just met Leah who's technically a teenager and technically Loki's creation/daughter and since the actual age of the minor(Loki) or nature of parenthood(Scarlet Witch, Miss America) doesn't seem to matter...
Wanda subconsciously chose the families into which Billy and Tommy were born.The twins' backgrounds oddly reflect her own background and parentage: Billy was born into the Kaplan family, honoring her father's Jewish heritage and Tommy was born into less-than-comfortable circumstances, with popular fan theory that he's at least part-Romani, honoring her mother's Romani heritage.
Loki's ultimate plan is to redeem himselfFrom the events of Journy Into Mystery, Loki seems to have come full-circle and destroyed any chance of redemption through the murder of his young self. But by now he's sick and tired of being the villain, which he now realizes is a doomed and static state of being. Loki wants to break out of his role, but knows that any attempt of pulling a full Heel-Face Turn would fall flat on its face due to narrative causality. He therefore put himself into the role of morally-ambiguous mentor to a Reality Warper and his friends, the only people who could conceivably help him break out of his role. Through their influence and his place among a team of white hats, Loki can finally change himself and his role in the Marvel Universe for good.
Billy will voluntarily give up his powersAfter all the trouble caused by his powers and the stupid decisions he's made with them not to mention they were the reason why Loki manipulated him into summoning Mother, so Loki could eventually get close enough to Billy to steal them for himself and especially after seeing all of the terrible alternate futures his powers may cause, Billy will decide that he'd be happier and the world would be safer if he gave up his powers for good. After learning what Loki's ultimate plan was, he'll do this in front of Loki to drive in the fact that someone can be happier without incredible power and that Loki has failed in getting what he wanted from Billy. It will also progress naturally from his decision in The Avengers: Children's Crusade to give up crime fighting altogether and with the addition of Prodigy, who has lost his powers as well, he has proof that he can live without his powers while still being part of the super hero community.
The series will end with a Pyrrhic Victory for LokiHe may end up getting Wiccan's god-like powers for himself and controlling the flow of magic, but getting there will require losing his teammates (which he may realize too late were actually important to him), the corruption and possible death of Leah, and finally he may realize that he's only trapped himself in yet another cycle of Ragnarok where he's doomed yet again to see his home and people destroyed, when he might have avoided getting trapped in his villainous role altogether.
The individual that knocked out/killed the Living Tribunal?The honest to badness Devil of the Marvel Multiverse. For those not in the know, New Avengers #8 has The Living Tribunal passed out, or possibly outright killed. Since he's second in power and rank to The One Above All , and so high-up that he doesn't care what Thanos with the Infinity Gauntlet does, what could even knock him out? Either something really WRONG is happening with The Multiverse, or there's a being on The Tribunal's level who hasn't appeared. Fear Itself has established that there is a Devil who's been gone so long nobody is sure he ever existed, and that his throne is something no demon dare sit on. This includes beings such as Mephisto and Dormammu. Any Devil with that street cred is one of the most powerful beings in all of Marvel, and probably the only one who stands a chance of even knocking out The Living Tribunal. What role he, she or it has been playing in the chaos across the multiverse is unknown, but whatever the case be afriad. Be very afraid.