Thess: that's a good analysis and might've been what they went for, but if that's what they wanted I think the writers really executed it poorly (I'm picking on them, not you), because there's been numerous prior occasions when Kagura's seen (or would at least know about) people outside the fated nexus doing stuff like what Zessica was doing for Amata: you have Jin giving up his life for Yunoha, you have Amata doing it for Mikono like three or four times (episode 5/6? again in 13? a few more times in 15?)...I'm probably forgetting a few here honestly, like Andy and MIX depending on how much of the Andy-MIXY battle he actually got a look at.
This isn't trying to say you're wrong at all, just pointing out that the writers didn't really to much to make explicit what specifically would've been different about running into Zessica vis-a-vis the previous scenarios...even so it's not like Kagura's the sharpest tool in the shed...
. Poorly executed but at least an idea that makes it seem like they had something in mind for it beyond just tying two loose threads together.