Ok so there's obviously a lot of confusion regarding the Alice Fiction collab, so let me squish some rrats with some of the stuff I've found.
The collab announcement stream - where Gura, Kiara, and several Niji livers were announced - was from the Alice Fiction official channel. And among both Hololive AND Nijisanji, only Ange had official "mirror stream" permissions for that stream.
And Ange was, therefore, the only chuuba who saw both Nijisanji and Hololive pop up on her screen -
https://youtu.be/rJ5RuRqRurs?t=2442The others - both NijiJP, NijiEN AND HoloEN - never had a mirror stream for this event. It was all separate sponsorship streams, and every single one of them obviously only showed their own company members that were collaborating.
No one in their right mind would complain if Hololive didn't show Nijisanji livers on their stream for a game they onlyl shared sponsors with after all.
From Niji side
Yashiro :
https://youtu.be/Wd4xGfptg7M (didn't show any other niji liver or holo)
Ngo :
https://youtu.be/Pno12dORnYg?t=4966 (only showed Nijis)
Nari Yang :
https://youtu.be/3O7jZy354rE?t=3668 (only showed Nijis)
Elira :
https://youtu.be/y1uSnx9QN7s?t=3426 (only showed Nijis)
Shu :
https://youtu.be/Odx55AlwhEI?t=3850 (only showed Nijis)
From Holo side:
Gura :
https://youtu.be/QlcwzBpJn6k?t=759 (only showed her own singing collab)
Kiara :
https://youtu.be/j1zBPms6R2k?t=5683 (only showed Gura and herself)