I would guess, naively, that as long as you stored all that info you collected in a legit way:
- line item properties
- cart attributes
Then Shopify would indeed maintain those and ensure they end up in the final order, just as they would through any non-accelerated checkout. I am sure you can test that theory in a matter of minutes by simply switching it on/off for accelerated checkout. There'd be no reason to lose that data, and you'd think there would be a huge kerfuffle if simple data structures were mangled just to accomodate checkout. Pretty sure you're good there.