Just saw your post about Rin/Hagoromo, now I'm so curious to hear about your other findings ??
Okay, so this is probably not the whole picture, but let's get into it.
Most of Naruto is a japanese mythology/folklore retelling. Which I think is important if you want to look for connections with charachters. Jiraiya and the slug princess, the eight dog warriors(kakashi's dogs), Konohanasakuya hime (sakura), Chidori and Raikiri were one samurai sword that got renamed.
The uchiha clan is usually connected to the amaterasu family. Susanoo defeating orochi, the legendary weapons like the yata mirror, the crows being amaterasu's messengers, ninigi (sasuke) leaving heaven and going to earth and meets a bunch of people. Izanami's body rotting away (Itachi). Kagutsuchi ( the fire god, the first child of izanami-izanagi) literally has the water goddes as a partner to pacify him (think itachi and kisame, sasuke and suigetsu)
Anyway. Hagoromo is Abe no seimei. The biggest onmyoji. Abe no seimei had main two descendant bloodline, like Hagoromo.
Abe no seimei's mother was a kitsune, that he defeated. Kinda like Kaguya.
Abe no seimei also had two powerful shikigami, but the only shikigami themed charachter we know is Konan. Who was actually acting as a shikigami for Nagato.
Now that the abe no seimei and hagoromo connection is established. There are probably more, but these are the main things.
And the Uzumaki continued with the sealing, carrying most of Hagoromo's legacy. (it would make more sense if the uzumaki was the other branch and not the senju, since the only other clan with a shrine was the uchiha in canon but whatever)
So, Rin. In my opinion, Rin is probably from an Uzumaki branch family. And the family name doesn't neccessarily matter, because the uzumaki were wiped. No one would want to be associated too obviously. Although Rin didn't get a surname until the war arc. And one could make the argument that her hair is a very reddish brown in the beginning:
Until the indra coloring came out and then it's clearly brown, although different shade as Indra's.
Let's go from the most obvious to the more subtle.
Let's start with the fact, the Rin is the only charachter who could watch the real world, and make herself tangible as a ghost. (Kushina had no idea what did Naruto talk with Minato, every edo tensei zombie's last memory is them dying, Sakumo didn't know anything about Kakashi, even Jiraiya tapping Naruto on the shoulder after his death was an anime only scene) (This used to be the only thing my theory was based on)
Obito was a special case because of Kamui and that was also only his intangible chakra.
Point two. The data book connects Rin to the bell flower. Calls her a bell flower. Now, there are multiple flowers that could match this, but Rin is autumn themed (more on this later) and also the whole thing with eternal love symbolism therefore it's the kikyo. The bell flower is the symbol of Abe no Seimei. That is mainly where the purple color for spiritual themed charachters come from. So it makes sense that the markings were purple and then went to match Indra's bluish purple.
Point three. The face markings match Indra's markings, which, connects her to the Hagoromo family.
We don't even know what was Indra's real eye color in canon. Although it might be the same as Ashura's.
Point four. Probably step 1, because I didn't research all famous miko. There aren't really famous onmyoji's that could match Rin.
The japanese folklore connection. There's a story where Amaterasu is in a cave and Ame no Uzume dances to get her out of her cave and the Amaterasu sees herself in a mirror when looking out and comes out.
Amaterasu (Obito) Ame no Uzume (Rin, more on this in a bit), the mirror (probably what Obito sees in Kakashi's sharingan, which mirrors him).
Ame no Uzume was a goddes, and the Kagura dance and some parts of the mikos job and 'powers' come from her.
Now this goes into the bit that was so circumstential, but that was all I had in the beginning of the rabbit hole.
Kagura dancers use a three layered bell that consists of multiple bells. This whole story with Amaterasu is where the miko's/Kagura dancer's ability to guide and and summon deities comes from.
Guruguru connects Rin to bells (with Obito calling out Rin-Rin), the bell flower being suzu no hana instead of kikyo and the data book describes her as a guide and Obito describes her as his guidance (and she was actually dragging Obito to becoming Hokage) and also Rin being a guide:
So this is the Rin-Bells-Miko connection in a nutshell.
And also, the Ame no Uzume celebration is in november like Rin's birthday. (Rin being autumn themed and autumn flowers are known for their resilience and well, Rin implanted an uchiha eyeball while her bestfriend was crushed to pulp)
Point five. It's turning subtle.
Rin's clothing is imo a miko-like. The 'ribbon', the shiluette, Hagoromo's whole get up was also black and gray so maybe that is also adding to it.
One could make the argument that the miko outfit actually comes from Rin being Nono's student,( since she doesn't do anything beside medical ninjutsu and she has a stat of 3.5 out of 5 while Sakura had 3 after timeskip. The medical ninjutsu training is systemized in Rin's time, but Tsunade has blood phobia, so she probably doesn't do much. Maybe fighting. That leaves Orochimaru and Nono to teach medical ninjutsu if one wants to get stronger. Anyway, that would be a whole other post with what was a kunoichi during the war in the narutoverse and I'm still looking into it.)
But the naruto world has a known theme of corrupting ninjutsu and everything into weapons of war. Like how the Nara's used to make medicine and they used their shadow jutsu to capture deer, or how the akimichi is mainly a medicinal family with vast knowledge that even Tsunade was surprised to see. (after sasuke rescue arc when choji was in the hospital)
(Also i'm pretty sure there was an omamori sewn into Kakashi's medical pack he got from Rin, but I can't find it anywhere.)
Rin's ability to turn herself tangible as a ghost has to be a very strong yang ninjutsu (which would honestly explain the 3.5 in ninjutsu when Sakura had 3 after timeskip). And this level I think could be connected to Hagoromo too.
But Konan's ability to turn herself into everything is also a Yang ninjutsu, and she is mainly Nagato's shikigami.
I don't know what connection could be here explicitly, but there could be something
But maybe I'm just reaching.