Vac-Man will appear eventually.
We've already seen (maybe) Stretch's biggest enemy of the '70s, so someone from the '90s sounds logical for a future villain, especially since Hasbro has recently started selling him again
.Kane's role in Season 2.
Given the slight amount of trust between him the Flex Fighters, I find it hard to believe that he'd believe that they'd turn evil. As such, a story arc in Season 2 will involve him slowly piecing together that Rook is evil, and acting as the team's Commissioner Gordon, feeding them intel to help them thwart Rook's schemes.- This theory is jossed as of "The Fall Of Jonathan Rook". It turns out that he's the leader of The Tech Men, thus making him a case of "Evil All Along". In addition, he knew that Rook was Stretch Monster all along, and was planning to overthrow him.
Wretch Armstrong will show up as an evil clone and Expy of Bizarro
Most Superhero cartoons generally need to have some form of Evil Counterpart or clone of the hero, and Wretch has a very “Zombie-esque” appearance, so he could easily be made to fill that role. Stretch Monster pulled off one of the best Xanatos Gambit in western animation
Whenever Stretch Monster comes in, he usually says at one point All According to Plan, and here's why: As Strech Monster he'd create supervillains to fight the Flex Fighters so he'd study the Flexarium to try and make Hyper Flexarium, which had only been made by Dr. Cleo. If the villains won, he'd control the city through them, if they lose, then Rook Unlimted would get a major share of the cities control given that Stretch Monster is Rook. And when he got the information for the Flexarium he needed, and the Applied Phlebonium from Blindstrike he would mass produce an army of Hyper Flexarium monsters to attack the city. If these monsters won, the Flex Fighters would be out of the picture, and if they somehow stopped the mass production, he'd still have the information to recreate the experiment. Then he would poison them and even if they survived that, then he'd brand them as terrorists working with Dr. Cleo and Blindstrike. The Vac-Men and Rook's true motivation
Since Vac-Man (or the Vac-Men) were originally interpreted as invading alien(s), this could be true for the series as well. Rook somehow found out about their attempts to take over Earth, and wanting humanity to become advanced and strong enough to fight back, initiates his attempts to push mankind both through advanced technology and the application of Flexarium.- Nope, Rook's obsession with improving humanity ends up being out of a combination of a genuine sense of altruism and trauma caused by his terminally-ill mother's death.
Riya might be Dr. Cleo's daughter
In Episode 12, Riya mentions that she needs somebody to talk to about problems with mom. Later that episode, She's revealed to be Blindstrike, Dr. Cleo's closest ally.- "Riya's Revenge" jossed the possibility of Dr. C as Riya's birth mother, and Chris Wyatt's recap of the flashbacks clarifies that Riya didn't literally mean to refer to the doctor as her mom.
This show will eventually join the Marvel Cinematic Universe.
I can see it happening.