It's been updated by one random dude who has his wires crossed because of the Kronii art 'leak' most likely and probably had the idea reinforced when he found out Kronii could speak Korean. I saw a few people making this assumption earlier today, but Sana is 100% without a doubt Namie who is Ina's close friend. The art style is exactly the same and the two have been interacting on Twitter for years.
I'm still of the belief Kronii is Seru who has, as one other forum member pointed out, down pitched her voice (while she was pitching up for Seru). The artist who leaked the Kronii art was an acquaintance of her, not Ina. and alongside this you have the fact Seru and Kronii's interests/likes/dislikes read like a carbon copy of each others.
And no, it's not Nerine, I would eat my hat if she got into a big company. Far too unstable.