That does seem more likely.
I think part of my confusion is that just before the vision, he's talking about how he remembered being on an airship with adventurers before - and any talk of previous adventurers is generally an indicator for "1.0 event reference incoming" - so I assumed the remembered scene on the airship was a memory of something that legacy players were actually present for.
Still, with no other context, it's a little hard to make sense of. I understand the WoL would be physically present in Echo visions in 1.0? But I don't think any other 2.0 scenes do that. At very least perhaps it needed to show us present and watching Cid before that point, to establish us as more of an observer-to-the-whole-sequence and rather than an 'event' of us appearing in one place and time.
I understand what was going on during the battle (except the Haldrath bit anyway), my issue is what we're shown/told of what happens after. It would make a lot more sense if we'd seen Estinien regain control of himself after we defeated him. Instead we see him snatched away by Nidhogg, and then Alberic tells us that he's missing and nobody has seen him since. And then he just turns up again in the MSQ like none of it ever happened - and for all I know, Nidhogg might still be controlling him. It took me a very long time to stop suspecting that was the case.
Even if his one line was changed, it could make such a difference. All he says in reference to it is "I'm not here to challenge you this day" - if instead he said something like "I wasn't myself the last time we met", that would work better.
I'd just caught onto Carvallain's no doubt purely coincidental resemblance to certain Ishgardian nobles at the point when I read the Tales From the Calamity, so I loved the reference.
That's a funny lopsided thing with our individual conversations with them though. Both are in blatant denial, but not each focused on the other - Carvallain's far too busy insisting he's not from Ishgard to talk about any not-feelings he might have regarding Rhoswen.
From what I've seen, at least (mostly Lv55 CUL and also an older Valentione's Day quest script), I don't feel like the dance is equally "they secretly like each other" as much as it's Rhoswen liking Carvallain, getting halfway to admitting it and doing something he'd really appreciate, him getting halfway to noticing, but then she steps back and doubles down on the "of course I don't like him" act - which makes him turn suspicious of her motives and the whole thing falls apart. Again.
Were they in 1.0? Did anything interesting happen with them?
Hmm yeah, Latin would make sense if they used it. I don't know any Latin though.