It's possible that it was a retcon.A rinnesharingan does not exist in the manga, there's only been 3 doujutsus. Byukagan, sharingan, and Rinnegan.
All you have is this fan-made translation of yours, I'm talking strictly manga and manga only. So you can't tie manga logic to unofficial translations to prove your point, that's a speculation.
Because the rinnegan chakra that is known to be part of hagoromoo's started from Kaguya herself. Chakra is the key here not doujutsu.
1. That is the official translation, so yes the whole thing was a guess. Hence why he said probably.
2. Unlike Hagormoo, Sasuke's never seen or countered IT before. So of course he doesn't know who is casting it. But Hagormoo is Kaguya's mother, he knows her powers, jutsus, chakra (since he's half of it) and he knows how to undo Infinite Tsukuyomi.
So of course he knows it's a sharingan. Just like he specifically stated that you need the rinnegan and biju chakra to break that IT that was casted by her sharingan. And the question arrives in who are you to question Hagoromoo, the overseer of the whole series? That's like you questioning black zetsu if hagormoo and hamura did seal kaguay up since Hagormoo never said he sealed his mom up with his brother when meeting naruto and sasuke.
I'll leave that to the official people who are licensed and paid instead of someone who's not.
I don't have to believe what your translations, I rather receive it from the author himself.
So if Madara used a Infinite Tsykuyomi on Obito with a sharingan, why are you denying Kaguya the same? Since you know a sharingan can be used for IT just as much as a rinnegan can be used for IT. What does that tell you already?
1-The people under IT reflected Rinnegan patterns in their eyes
2-Sasuke called it Rinnegan Genjusu...the doubt was only on whether a Rinnegan could break it.