To be completely honest, I lack the personal experience, expertise, and/or eloquence needed to give a satisfactory answer to this question (hence why I work within the bounds of what the lore tells us), so I’ll provide a summary, links to informative threads, and what we can surmise based off of AKATSUKI’s (scant) interactions in Okinawa.

Here's a summary from The Rising Powers Initiative

"Okinawans, formerly known as the Ryukyuans, existed as the Ryukyu Kingdom since the 13th century until Meiji Japan forcefully annexed the island nation. Under the Japanese colonial rule and assimilation policy, the Ryukyuans lost their own culture, language, land, and political institutions."

Here are a few threads that I think get at the very real political implications from people who know the subject more extensively than me: @mika_enstars - a summary about the relationship between japan and the ryukyuan kingdom, and how that applies to AKATSUKI and Ibuki's identities @gitsunegal - on potential implications of cultural assimilation, should the writing be mishandled

I personally agree with them in that, if the writing direction were to be mishandled and AKATSUKI were to "assimilate" Ibuki from his Okinawan heritage, it would be very disgraceful. That being said, speaking within the limited bounds of the lore (since AKATSUKI hasn't had much to do with Okinawa since Submarine), I think canon somewhat suggests that Keito and Kuro appreciate Okinawan culture.

|| When AKATSUKI steps foot in Okinawa (Submarine, Ruthless Battlefield 2):

Keito: The weather is so pleasant, it doesn't feel like it's winter. Seems we’ll make some good headway on our idol activities.

Souma: Heheh. You’re talking quite a lot more. It’s unusual to see you in such high spirits, Hasumi-dono.

Keito: Is that a bad thing? Temples are rooted where they stand, and I’ve rarely left my hometown. It makes my heart race just to set foot in a distant place like this. How fun.

|| When Kanata offers Keito a dish in Okinawa (Submarine, Ruthless Battlefield 4):

Kanata: alrighty, [make way] for all of the [food]. temple guy cannot eat [meat or fish], right~ so here’s a [salad] ♪

Keito: My family isn’t as strict as that. Still, these sea grapes are so Okinawa-esque, I’m a little delighted.

|| When AKATSUKI are performing on the live stage with their costumes (Submarine, Epilogue 2):

Kuro: The outfits we're wearin’ now were commissioned by ES and made by the local Okinawan people. It suits the local climate and it’s got an Okinawan feel. It’s sure to be a hit with the tourists too. I think it’s a real honor to get to wear ‘em.

Keito's thesis gets mentioned in VS AUDIENCE: taking the traditional performing arts and evolving them into something one of a kind. I want to have faith that “traditional” could mean highlighting Ibuki’s traditional customs. With how much Keito appreciates Ibuki and what he brings to the table, I would be severely disappointed if the writing were to turn in a way where Keito stifles a key aspect of what makes Ibuki Ibuki.

TL;DR If the writing around Ibuki joining Akatsuki is mishandled, there are very dire political implications to it, and they should certainly be called out. However, from a character-perspective, it's possible AKATSUKI could adopt Ibuki's customs if he were to join, given that AKATSUKI's thesis is "taking tradition and evolving it into something new".

But it's very much a question of "we have to wait and see when it comes out."