If we
need to reference the anime plotline, I think this works well. Both the event and the triplets instead of Elan, clone Elan 4, and clone Elan 5. The birthday can't be nearly so... yknow.
There's no way to write Elan in this arc that won't tick people off. Including me~ The anime's het flirting was interesting even if uncomfortable because it showed SuleMio wasn't a healthy relationship at that time. It's still Suletta being an airhead and causing grief for Miorine.

Push your girl against that wall and cement the relationship, Miorine!
We're a few arcs early from that 'basically confession' and probably won't get a reprise of the funny yet painful accidental tit punch
In this fluff version, Suletta and Miorine are closer faster. The early snideness from Miorine's fears and prejudices was excised, which makes the yuri more mutual earlier. Anime Suletta at this point seemed attracted to Miorine['s legs] but Miorine's mixed signals were confusing, and
verbally set a nonromantic distance.
Here: Miorine is less guarded against Suletta, so birthday boy isn't a romantic challenge. No implication Elan actually being friendly and flirty would have a romantic value that Miorine is failing to fill beyond being blunt it's romantic. Instead it's an aquarium date that is going to tick Miorine off but she doesn't need to play catch-up in Suletta's bi heart because Miorine isn't fumbling conversations and discomfiting the purehearted homeschooler. At worst Suletta may have a bit of comphet assumptions, but Elan can't come between these useless sapphic besties beyond giving Miorine a fright.
I liked the Elans as characters, but not all their necessary plots. So for me this is about ideal for a peacetime reimagining. Miorine's jealousy is important to make her more honest and openly romantic; this is hardly the worst case of missed opportunity leading to regret in yuri. So not a comfy plot but it did work in the anime.
I'm guessing Peil is going to try to get Elan to lie and spy on Suletta, again, maybe less weirdly love-hate on sadboi's part. This route he could get expelled and
that be what moves corp politics to send his ambitious brother to Asticassia as a replacement.