In her own series, Jenny had previously joined a group called Teen Team. Teen Team and Team Teen, while do sound similar, does have some differences if look closely on their naming. Teen Team emphasizes more on the teenager aspects while Team Teen emphasizes more on the team aspects. Makes even more obvious when Teen Team ultimately broke up while Team Teen remained together, with Jenny even staying with that group longer than she had with the former.
Following up with the above point, both Teen Team and Team Teen have counterparts to one another.
Amazing Orion and Kim Possible are The Leaders to their respective groups.
Stupendous Squish, Ben 10 and Jake Long are all shapeshifters.
Misty and Danny Phantom possesses ghost-like abilities.
Aku having access to the Multiverse. In the premier episodes of Samurai Jack, Rothchild III explains that Aku opened up Earth to the greater universe and started plundering other planets because ruling Earth alone wasn't enough for him. So even if Jack didn't make it back to the past, thus necessitating the use of the Multiverse as an escape from his timeline's erasure, it would make sense that Aku would look into conquering other universes when he eventually got bored with ruling his own.
When does this series take place in regards to the continuity of all the shows featured therin? Judging from certain visual cues as well as spoken Continuity Nods, we can assume it takes place:
After Weirdmageddon, as the Pines Twins were seen attending school. Dipper and Mabel even say that they met Team Teen and the others right before Weirdmageddon.
After the finale of Samurai Jack, as we see Aku sending his fragments across the Multiverse after Jack and Ashi go back to the past.
Either during or after Season 2 of American Dragon: Jake Long, as Jake's dragon form is sporting the slimmer design from that season.
During Season 1 of Star vs. the Forces of Evil, as Star's Wand is sporting its Season 1 design and hasn't been cleaved.
Then again, her appearance in Convergence was right before Weirdmageddon, so it's possible the events of Season 2 are taking place by the time Battle of Beach City is occuring.
During or after Season 4 of Kim Possible, since we see Kim sporting her Battle Suit from So The Drama.
Remember when Bill invoked the Axolotl that he may return a la reincarnation in "a different form, a different time"? Bill's resurrection via Aku is NOT that reincarnation. Though Bill was reformed via Stan regaining his memories, he was still in millions of little pieces because of Stan's punch and was left in a weakened state thanks to the Memory Eraser. Bill himself even stated that he wouldn't piece himself back together before Stan died of old age and that would've been the end of him. Aku's resurrection of Bill is most likely an interference to the Axolotl's spell, as Bill's new body is essentially his old one with a fresh coat of paint. Bill's true reincarnation will begin only when every trace of his old form is completely destroyed.
Rath getting beaten by Kim is a nod to the times she's beaten Dr. Drakken and Motor Ed, voiced by John DiMaggio who also voiced Rath.
Bill is actually WEAKER in his new Aku form.
He may have the latter's shape-shifting and mind control abilities, but in addition to being more vulnerable, he no longer seems to have his god-level Reality Warper powers since Ford destroyed them with the Memory Eraser.
Also, since Aku's essence is the main composition for his new body, Bill is all the more vulnerable to potential hazards that could hurt or kill him, as demonstrated by Rick's chemicals, making the likelihood of Bill dying permanently all the more possible.
Danny and Jenny's reactions towards Rick Sanchez reflects how their parents view the man. Both Jack and Maddie Fenton are good-hearted folks who would have a positive view about the scientist while Nora Wakeman is a cynic who sees Rick in the worst light.
The members included into the Multiverse group opposing Bird Aku makes complete sense.
Aku was previously defeated by powerful elemental beings in his series and Avatar Aang is a powerful elemental manipulator.
The reason Jack's sword can harm Aku is due to it being forged from the power of righteousness. Can't be any more righteous than someone with the Power of Friendship like Twilight.
Having Star Butterfly on the Team will be a major boon to the heroes. With Aku's virus being a multiversal threat, the Team will need someone who can easily access the Multiverse, like Star and her Dimensional Scissors.
In Resurrection, before the Aku fragment went after Stanley's mind to bring back Bill, it first tried to attach itself to Morty. Consider the fact that the Aku Virus is attracted to sources of evil. Then, if you recall all of the traumatizing stuff that canon Morty goes through on Rick's adventures, some of his own rather unscrupulous actions, and the fact that there's at least one canonical EVIL Morty roaming around in the Multiverse, it really makes you wonder; just how much evil did Aku see in this particular Morty?
Since anime characters likes Izuku Midoriya and Yugi Muto exist, their enemies also exist as well. Imagine if Aku infect the likes of All For One, Frieza, or Dio Brando.
