I've grown interest in this topic because I am, in a sense, fascinated and obsessed with Jetix.
I've never kept that a secret. I wear a Jetix hat all the time out and about, but it does still suck to see much of the BVS library stuck in corpo limbo. It's a moment where I wish Tubi, who are known to acquire obscure cartoons quite easily that most streamers end up neglecting, were able to strike a deal.
But I then remember who owns Tubi, and I feel like Fox isn't willing to open a can of worms to that degree cause, while Tubi has a really good offering of kids content, not just of the recent Warner Bros content, and ironically some of the Fox Kids shows that were distributed outside of BVS/Saban, I don't think Fox and Disney are really wanting to go through all the monotonous copyright paper work to see who owns what and what they can legally air or stream. In a sense, neither one of them is willing to pick up the toys. Fox Corp, the new one, wasn't built to go through legal properties as anarchic as their former partner Saban was, and in a sense, I feel like they want to forget their past due to the fact that the old Fox Corporation was a bloated and impossible mess for them.
But don't get it too twisted: I think Disney do still have the broadcast tapes of all of the BVS content. A.T.O.M, Diabolik, hell, even Pittsburg Pigs for that matter. Disney aren't a corporation who like to forget things or their own history. If Steamboat Willie can be archived, then so the hell can Eek. Hell, I probably think there are some folk within the legal departments of these companies who probably do, like ourselves, want those shows to be out there but because of the mess that is copyright and legalities, they just can't.
If Tubi saw the demand for these shows, then they totally would get them on board. But there's so many people you have to contact, the actors, the directors, everyone involved. And it's possible one of them may say no or demand more money.
I do wonder if you've considered contacting the external parties about it besides the main copyright holders. I personally think it should be within your best interests to start looking at the directors, the writers, the French/Canadian studio reps who helped make these shows, not to ask them where they have them (because they most likely don't), but to ask whether or not they'd be okay with them being re-released or streamed. They have the final say after all. Paper trails always tend to throw you in a loop, but for animation, they're always as easy as an email or contact. And hell, maybe Disney and/or Fox may be less worried about the legal ramifications.
TL, DR: Be the change you wanna be. Start contacting directors, writers, etc. behind these cartoons. It's far easier to start a paper trail than demanding a multi billion corporation like Disney to release them.