Anyway I have a reason to suspect that Rice/Oro fanclub is behind Akane. (Yes I have a tinfoil hat, why do you ask)
The first is more of a meta reason, the colour court and Rice both share colour themes:
"Well," Okamura paused to take another bite of his meat, "the Murano, the yellow clan
And their replacements in Sarubetsu's political arena are the Hinago, the violet clan.
"I don't know what the Harada's sphere of influence was, but I suppose they must have lost it, or maybe they had to allocate their resources somewhere more important. You don't see green much in the south anymore.
And there is also
(Not a good proof, but more colour naming)
Maybe this is how they meet, send secret representatives to deal with each other to avoid to much direct conflict.
My second reason is that the Hinago are interested in Biosealing or are actual ones, because they were the once who wanted Arikada:
"Uh-huh," Noburi said. "While we wait, you mind telling us why this place is so quiet? It feels like a haunted house."
"Oh, they're nervous about something to do with sealcrofting," Ichiru said. "They said something to me about being polite and not making any sudden movements, but I was too busy evalumating my new formula to pay much attention. I wouldn't worry too much about it if I were you.
And are also part of Orochimarus fan club,
(Same dude):
You know what they say, the serpent is in the details.
(Hinago we met in Mist during chunnin exams):
"Not now, girls," Hinago said wearily. Hazō noticed her hand moving surreptitiously towards the snake-patterned pouch at her waist. "Do I need to remind you that the Moon Princess will awaken in six rounds if we don't do anything?"
My third reason is that we encountred a Bioseal that turned Naruto into a cannibal and that was one of Orochimarus
old seals, before he went missing-nin. So some form a Bioseal could have influenced Ruka to assign Akane some mission they could easier monitor. ("Send Goketsu West"). Also, Rice isn't really far away, they could wait and rotate teams very easily.
Thanks to our civilian sealing stuff, nobody would even suspect some civilian carrying some seals around, so our "insider" could be anyone.
And last, our Biosealing friends from Isan who are part of the same network were offered adoption at some point, maybe they enter Leaf every once in a while.
Killing Akane might not even bother them. Just resurect her for a time and squeeze information out of her.
TLDR: Let's grab some Biosealmasters from Rice, lets gooooo