Right before the game releases, the official twitter page of Xenoblade Chronicles 2 posted this.
Last edited by Hiku - on 02 December 2017
"No information was shared for KOS-MOS Re: in the game, but she has gone beyond the barriers of the series and will appear in Xenoblade Chronicles 2 as a Rare Blade. She’s voiced by her original voice actress Mariko Suzuki who voiced in the Xenosaga entries. She’s designed by Kunihiko Tanaka, best known as the character designer for Xenogears, Xenosaga: Episode I, and Xenoblade Chronicles X."
Alright Monolith, take my money. (If/when I buy a Switch.)
She has her original Japanese voice actress too. Sounds like she has a new one in English though.
Hopefully Bandai Namco release a Xenosaga HD Collection as well in the near future. Perhaps if .hack//GU does well.
And on second thought, I edited out KOS-MOS name from the title in case people don't want to know what cameo characters are in the game. But since she's just a blade/weapon, this is the kind of thing that would make me more interested in the game.
And I see that this was already posted by someone. It just wasn't on the first page.
Also, difficult for me to check the content of Xeno 2 topics that say spoiler in the disclaimer.