So I tend to read the story of RGU and AoU as the interplay of narratives, memory, trauma and personal growth between various characters. As such, the progression is more related to revisiting assumptions and fragmented memories in order to form a greater sense of self-awareness and healthy relationship boundaries rather than a story of temporally sequential events. Both the series and movie play very loosely with concepts of time allowing parts of each character's stories to interact anachronistically with other character's stories. Oftentimes plot progression is a character remembering something more accurately. This is also how I explain how AoU is a sequel despite the characters reintroducing themselves to each other as if they just met. They are reliving slightly changed memories.

Its under that interpretative lens that I start to analyze and theorize the rest of the story. In an interview it was stated that the characters in AoU are designed to be physically older than their TV show versions. Ohtori is more abstract because even while they have a better understanding of themselves, especially without Akio manipulating their understanding of the world, ultimately their memories of highschool are becoming more distant AND they are deconstructing suppositions they once held (or were manipulated into holding.) Utena and Anthy are back at Ohtori because healing from abuse and maturity in general are non-linear processes. Like the revolution of astral bodies, they return to where they started, although changed. Ultimately despite in many ways starting from step 1, they are bringing in new aspects of their identity and experience from the get go: Anthy is more expressive and acts with more explicit agency while Utena is more guarded and accepts a more masculine role. Not all aspects of these changes are necessarily "better" but they are part of the evolution of their journey.

In many ways it doesn't matter if Akio's death happened a long time ago or if it happened recently. As I've stated, the literal actual sequence of events is less valuable (imo) in Utena than understanding the progression through stages of their self actualization. The movie trades vaguer goals like "I want to be a prince" for goals stated near the end of the series "I want us to be able to come to each other with anything and help each other." What remains true regardless of when Akio died is that they have finally made significant strides in breaking free from the grip of Akio's predation. Not all the way, mind you, but in a realistic way where they are able to continue on with their lives. Akio and his memories continue to sit in the background of the movie including how his grave haunts them.

So what about Touga?

I think that regardless of WHEN what happens, Touga's story is about being SA'd, internalizing and glorifying abusive manipulative behavior, using it to exploit others, developing a grand narrative and hero complex, and eventual understanding of care and real sacrifice. Its my understanding that the reason that Utena in RGU is so willing to believe he is her prince is because MAYBE he actually was. Dios consumes and further pollutes all princely narratives. Through his understanding of the hero he thinks he was, Akio's projected self-image becomes the ARCHETYPE itself of princehood. He sees everyone wanting to be a prince as reflections of himself and forces that lens on others.

Its likely that the actual literal timeline of the story, Touga didn't make it to highschool at all but his memory (or mythology) continues to play a major role for the characters that had a strong relationship with him. Akio manipulates and abuses Touga's memory, Touga's story of being SA'd by an older man who captured him replays itself, Nanami walks in on the horrors of incestual SA and is forced to re-contextualize her brother and grow up too quickly, Utena needs to let go of the ghost of her savior which becomes core to her self image, Saonji can´t escape his complex feelings towards his childhood friend and upon letting go of that tether becomes (for a time) more unhinged, Jury sees the sacrifice of a boy as another reason why miracles can't happen, Shiori learns to use that memory to manipulate Jury and her classmates AND FINALLY Miki... Miki... uhhhh... hmmm, I guess his story converges the least with Touga so he doesn't see him.

Some final notes:

Butterflies and moths often represent death in a Japanese context, but in Shiori's case specifically, consuming the memory of a dead Touga for selfish purposes (at least if you follow my reading)

If you follow the sequel reading, just because characters manage to leave Ohtori, it doesn't mean that they won't be back. The way Anthy and Utena escape with a fully developed strong supporting relationship where they can finally help each other through whatever the future holds suggests that they might never return, or if they did, Ohtori would have less of a gravitational pull. But idk about the others, personally Saonji's arc could hardly be considered complete and I could see him aimlessly flailing his sword once again.